How to Write an O-Ring RFQ (Free Template Included)

An O-ring RFQ that says "please quote 1,000 black O-rings" triggers a minimum of three clarification emails before a supplier can respond — adding 3–5 days to your procurement timeline before quoting even begins. A complete RFQ gives the supplier everything needed to respond within 24 hours with an accurate price, confirmed lead time, and material recommendation. This guide covers the eight fields that make an O-ring RFQ actionable, the most common mistakes that delay responses, and an example email you can use directly.

Quick answer: Eight fields make an O-ring RFQ actionable: (1) size — AS568 dash number, ISO 3601 code, or ID × CS in mm; (2) material — compound family, Shore A hardness, color; (3) operating conditions — fluid, temperature range (min and max), pressure, static vs. dynamic; (4) quantity — initial order and annual estimate; (5) required delivery date; (6) certifications — ISO 9001, FDA 21 CFR, USP Class VI, NACE, etc.; (7) documentation — CoC standard, MTR required for aerospace/pharma; (8) packaging — standard or cleanroom. Missing annual volume estimate is the single most common omission that shifts pricing from volume-tier to spot-order rates (typically 20–35% higher).

Why RFQ Quality Determines Quote Speed and Accuracy

A detailed RFQ accomplishes three things a vague email cannot:

1. Eliminates clarification cycles: Each round of clarification adds 24–48 hours to the quote timeline. For a standard O-ring in a known application, a complete RFQ receives a quote within hours; an incomplete inquiry may take a week to resolve.

1. Enables material recommendations: When operating conditions (fluid, temperature, pressure, dynamic vs. static) are included, a supplier's engineering team can flag potential issues with the specified material and propose alternatives — a lower-cost compound that also qualifies, or a recommendation to upgrade from NBR to HNBR based on the operating temperature.

1. Unlocks accurate pricing: Annual volume estimates allow suppliers to quote on the full commercial relationship, not just the spot order. A 500-piece RFQ with a 5,000-piece annual estimate typically receives 20–35% better pricing than the same 500-piece inquiry without volume context.

The 8 Essential RFQ Fields

1. Size and dimensions

Provide one of the following — in priority order of precision:

• AS568 dash number (e.g., AS568-214) — preferred for North American equipment; the most unambiguous size specification
• ISO 3601 size code (e.g., 25.00 × 3.53 mm) — preferred for European and international metric equipment
• JIS B 2401 series and number (e.g., JIS P25A) — for Japanese equipment
• ID × CS in mm or inches with tolerance class — when the standard is unknown or it's a custom size
• Dimensional drawing (PDF or 2D CAD) — definitive for non-standard profiles

Tolerance class: If the application requires tighter-than-standard dimensions, specify the class:

• AS568 Class 1 (commercial standard): ID ±0.25–1.02 mm depending on size; CS ±0.08–0.13 mm
• AS568 Class 2 (precision): ID ±0.13–0.51 mm; CS ±0.05–0.08 mm
• ISO 3601 Grade N (standard), Grade S (special), Grade CS (close special)

For aerospace, medical, and semiconductor applications, always specify Class 2 / Grade S or CS explicitly.

Groove dimensions as fallback: If you do not know the O-ring size but can measure the groove, provide: groove depth (d), groove width (W), bore or rod diameter, and whether it is a face seal, piston, or rod groove. A supplier can calculate the O-ring size from groove dimensions.

2. Material specification

Specify material in order of detail:

• Material family: NBR, FKM, EPDM, HNBR, VMQ (silicone), PTFE, CR (Neoprene), PU (polyurethane), FFKM
• Hardness: Shore A value (e.g., 70 Shore A standard; 90 Shore A for high-pressure hydraulics)
• Color: Black is standard; brown is common for FKM; red or blue for food/pharma identification; green or orange for specific compound identification in mixed-material facilities
• Specific compound specification: If you have an existing compound spec (e.g., AMS-R-83485 for FKM aerospace, Parker V747-75 equivalent, or an in-house compound number), include it

If material is unknown: Describe the fluid, temperature, and pressure instead of guessing. Do not specify "NBR or equivalent" if you have not verified NBR is compatible — let the supplier do the chemical compatibility check. Incorrect material specifications that are then manufactured exactly as specified are a buyer's responsibility.

For specialty compliance: FDA 21 CFR §177.2600 (food contact), USP Class VI (pharmaceutical), NSF/ANSI 61 (potable water), NACE MR0175/ISO 15156 (sour gas), and AS9100 (aerospace) are compound-specific certifications — not supplier-level certifications. Specify which compound certification is required.

3. Operating conditions

This is the most valuable engineering information in an RFQ. Minimum required:

• Fluid media: Be specific — "hydraulic oil" is insufficient; "synthetic ester-based fire-resistant hydraulic fluid (ISO Type HFDU)" is actionable. For chemical service: include concentration and whether it is a process fluid or cleaning agent
• Operating temperature: State both minimum (including cold-start conditions) and maximum (including transient peaks, not just steady-state). Cold-start at −30°C followed by steady-state at +120°C is a very different requirement from steady-state +120°C alone
• Maximum system pressure: In bar, MPa, or PSI. State whether it is static peak or dynamic cyclic pressure
• Application type: Static face seal, static radial seal, reciprocating dynamic, rotary, or oscillating — determines compression rate specification and whether backup rings are needed
• Duty cycle: Continuous service vs. intermittent; how many pressure cycles per day for dynamic applications; SIP/CIP cycle frequency for food/pharma

The cold-start omission problem: The most common missing data point in O-ring RFQs is the minimum temperature at cold start, not just steady-state operating temperature. A seal in a chemical plant that operates at +150°C but sits at −20°C ambient during shutdown must maintain sealing when pressure is first applied at −20°C. Standard FKM is adequate at +150°C but marginal at −20°C — this cold-start requirement changes the material specification.

4. Quantity and delivery schedule

• Initial order quantity: The quantity for the first purchase order
• Annual estimated volume: Total consumption across all purchase orders over 12 months — this drives volume pricing. Even a rough estimate (e.g., "approximately 3,000–5,000 per year") is far more useful than silence
• Required delivery date: Specify the date you need parts at your facility — not a vague "ASAP." Include any hard deadlines (equipment commissioning, production start dates)
• Preferred shipping: DDP (Delivered Duty Paid — supplier covers all freight and import duties), CIF, FOB. DDP is the most buyer-friendly option and eliminates customs surprises
• Urgency level: If this is an emergency replacement for production downtime, say so — reputable suppliers have express production lanes for urgent MRO orders (3–5 days for stocked compounds)

5. Quality certifications and documentation requirements

List certifications needed — both at the compound level and the supplier quality system level:

Batch documentation: Specify whether you need a Certificate of Conformance (CoC) and/or material test report (MTR) with each shipment. A CoC confirms the batch meets the specification; an MTR includes actual measured test results (hardness, tensile, elongation, compression set) for the specific production batch. MTR documentation costs more and is standard for aerospace, medical, and oil & gas applications.

First Article Inspection (FAI): For new custom sizes or new suppliers, state whether you require an FAI report before accepting production quantities. FAI requirements should include dimensional report, visual inspection per ISO 3601-3, hardness, and physical properties.

6. Tolerance and inspection requirements

Standard commercial tolerances (AS568 Class 1, ISO 3601 Grade N) are acceptable for general industrial applications. Specify departures:

• Tighter tolerance: AS568 Class 2, ISO 3601 Grade S, or custom tolerance (e.g., CS ±0.05 mm) for precision hydraulics or aerospace
• Inspection method: Optical comparator, CNC video measurement system (preferred for Grade S), laser micrometer
• Sampling plan: AQL 1.5 for critical defects, AQL 2.5 for major — reference ISO 2859-1. For aerospace and medical, 100% dimensional inspection is standard
• Defect classification: Reference ISO 3601-3 or AS568 Appendix B for surface defect limits and classification by severity

7. Packaging and labeling

• Standard polybag packaging is the default for industrial supplies — state if different packaging is required
• Cleanroom packaging (class 100 / ISO 5, double-bag per SEMI F57) for semiconductor and medical applications — this adds cost and lead time; specify the cleanroom class required
• Labeling requirements: Lot number, cure date, compound number, quantity per bag, customer part number
• Shelf life labeling: Cure date and recommended storage date are standard; specify if shelf life per SAE AS5316 (aerospace storage standard) needs to be printed
• Export packaging: ISPM-15 phytosanitary certification for wood pallets shipping to North America, EU, and Australia; state if required

8. Target price (optional but valuable)

Sharing a target price or a previous supplier's quotation is not a negotiating weakness — it is useful information that helps the supplier structure a competitive response. It signals: budget realism, seriousness of the inquiry, and gives the supplier context for proposing alternatives (lower-cost compound, different standard size, cord-spliced vs. molded) that might meet performance requirements at or below the target price.

RFQ Completeness Checklist

Before sending your RFQ, verify each field:

Common RFQ Mistakes That Delay Quoting

Example RFQ Email

> Subject: RFQ — FKM O-Rings, AS568-214, 500 pcs + 5,000/year > > Dear Engineering Team, > > Please quote the following O-ring requirement: > > Size: AS568-214 (ID 24.99 mm × CS 3.53 mm), AS568 Class 1 tolerance > Material: FKM (fluorocarbon rubber), 75 Shore A, brown > Compound requirement: Compatible with synthetic ester hydraulic fluid (Skydrol 500B-4) > Operating conditions: −20°C cold start; +150°C continuous operating temperature; 210 bar static pressure; static radial seal > Quantity: 500 pieces initial order; annual estimated volume 5,000 pieces > Certifications required: ISO 9001 (supplier); RoHS and REACH declarations required; batch Certificate of Conformance with actual test results required per shipment > Delivery: Required at our facility by 2026-05-15; DDP to [City, Country] > Packaging: Standard polybag, 50 pieces per bag, lot number and cure date labeled > Target price: USD 0.85–1.10 per piece at 500 pieces > > If FKM Type A 75 Shore A is not the optimal specification for Skydrol service at +150°C, please advise on the preferred grade. We are open to material alternatives if they provide better performance or cost. > > Please confirm lead time, unit price at 500 pcs and 5,000 pcs, and whether you have this material in stock for express production. > > Regards, > [Your Name]

Note what this email accomplishes: zero clarification emails needed before quoting; the supplier has fluid, temperature, pressure, standard, certification, quantity, delivery date, and target price — everything required for an accurate response within 24 hours.

FAQ

Q1: What if I do not know the correct material?

Provide the operating conditions — fluid, temperature, pressure, and whether the seal is static or dynamic — and ask the supplier to recommend materials. Include: "We are open to material recommendations based on operating conditions listed above." A competent supplier will respond with 2–3 material options with brief justification and pricing for each. Do not guess a material and then ask "is this correct?" — that creates a yes/no response rather than a recommendation.

Q2: Should I send a drawing with the RFQ?

Yes, always attach a drawing if you have one — even a dimensioned sketch. For standard O-ring sizes (AS568 or ISO 3601), a drawing is not strictly necessary if you reference the dash number correctly. For non-standard profiles (quad rings, D-rings, T-seals, face seal gaskets), a drawing is mandatory — there is no other way to define the geometry unambiguously. PDF drawings are standard; DXF or STEP files are useful if the supplier does in-house tooling design.

Q3: How quickly should I expect a quote for a standard O-ring?

For standard AS568 or ISO 3601 sizes in common materials (NBR 70A, FKM 75A, EPDM 70A): 4–24 hours for a complete quote with a complete RFQ. For specialty materials (HNBR, FFKM, high-ACN NBR, platinum-cured EPDM): 24–48 hours. For custom sizes requiring new tooling: 48–72 hours (tooling quote and production lead time estimate). If a supplier takes more than 5 business days for a standard O-ring quote with a complete RFQ, they do not have the engineering or inventory infrastructure to be a reliable partner.

Q4: Should I send the same RFQ to multiple suppliers simultaneously?

Yes — 2–4 suppliers for standard applications. Comparing responses reveals: price range (outliers in either direction deserve investigation), technical competence (suppliers who ask relevant follow-up questions or flag material concerns are more reliable than those who quote without questions), and lead time capability. The supplier that challenges an assumption ("the specified compound may swell in Skydrol at +150°C — did you consider Type GF FKM?") is demonstrating engineering capability that protects you from field failures.

Q5: Is it acceptable to share a competitor's price in an RFQ?

Yes — sharing a target price or a previous quotation is a standard procurement practice. It helps the new supplier calibrate their response and propose alternatives if they cannot meet the price at equivalent specification. It also signals that you have market knowledge and are not an unsophisticated buyer. Reputable suppliers treat price sharing as useful context, not as pressure to reduce quality — if a supplier responds by questioning whether they can match price at equivalent specification, that is appropriate engineering dialogue.

Q6: What should I include for food-contact or pharmaceutical O-ring applications?

State this explicitly in the first line of the RFQ: "This seal will contact [food product / pharmaceutical product / potable water]." Then list:

• Required compliance standard: FDA 21 CFR §177.2600 (US), EC 1935/2004 (EU), NSF/ANSI 61 (potable water), USP Class VI (pharmaceutical), 3-A Sanitary Standard
• CIP/SIP chemistry if applicable: "Cleaned with 1% NaOH at 80°C + 0.5% HNO₃ at 70°C; sterilized with saturated steam at 121°C"
• Whether compound-specific test reports are needed (required for medical devices; recommended for pharmaceutical)
• Color requirements (blue EPDM for dairy, red VMQ for food, translucent for pharmaceutical)

Q7: What is the difference between a CoC and an MTR?

A Certificate of Conformance (CoC) is a supplier declaration that the delivered batch meets the applicable specification — it states conformance but does not include measured values. A Material Test Report (MTR) includes the actual measured test results for the specific batch: measured hardness (Shore A), tensile strength (MPa), elongation at break (%), compression set (%), and any other tested properties. For general industrial supply, a CoC is standard. For aerospace, medical, oil & gas, and semiconductor applications where root cause analysis after a field failure requires traceability to actual batch properties, MTR documentation is required. Always specify MTR rather than CoC if your quality system requires traceability.

Q8: How should I structure a multi-line RFQ for a complex equipment overhaul with dozens of different O-ring sizes?

For multi-line RFQs covering full equipment seal kits or comprehensive overhaul bills of materials, structure the inquiry as a spreadsheet attachment with one row per part number, supplemented by a cover email with the common application conditions that apply to all or most lines. The spreadsheet should include at minimum: your internal part number, AS568 or ISO 3601 size designation, material and hardness, quantity, and any line-specific certification notes. The cover email should state: equipment type, operating fluid(s), temperature range, and which quality certifications apply to all lines. Common mistakes in multi-line RFQs: listing quantities without indicating whether they are per-equipment or annual; mixing metric and inch size designations without clearly labeling which system each line uses; and omitting the application (the same compound may qualify for some lines but not others). For kits with mixed materials (some NBR lines, some FKM, some EPDM), mark the material on each line — do not assume the supplier will group by material type. Lead time and pricing for a 40-line RFQ are proportionally similar to a single-line RFQ if the information is structured clearly; without structure, each clarification round adds 1–2 business days to the response.

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Ready to submit an RFQ? Use our quote request page — it includes all 8 RFQ fields as structured form fields so you never miss required information. We review all RFQs within 24 hours, provide material recommendations at no charge, and supply from MOQ 1 piece with 7–15 day standard lead time and 3–5 day express for stocked materials.