Part-number cross-reference
O-ring cross-reference tool
Type an O-ring part number or a size and this tool shows the size and the document behind it: AS568 dash numbers such as AS568-214, 2-214 or 214, mil-spec and SAE part numbers such as MS28775-214, M83248/1-214 and AS3209-214, NAS1611 and NAS1612 part numbers with or without the -A suffix, ISO 3601-1 metric sizes, a size typed as inside diameter x cross-section in millimeters or inches (55 x 2 mm, 55MM ID x 2MM CS, 1.234 x .139), and the NSNs on our part pages, each with its dimensions and the page to open.
How to use it
- Type the part number as your print or your last purchase order reads it.
- Read the size: the AS568 dash or the ISO 3601-1 code, with the inside diameter and cross-section in inches and millimeters and their tolerances; for a size that is not a listed size, the listed sizes nearest to it by both dimensions.
- Read the document: the specification, the compound and the status on file, and the other part numbers that name the same size under a different document.
- Open the part or size page for the records, or request a quote for the part number the tool read.
The size and the material cross by different rules, which the part-number cross-reference guide sets out. This tool answers the size half and names the document; whether a part made to one document may replace another is the decision of whoever owns the print.
Part-number families the tool reads
4,545 mil-spec and SAE part numbers under 17 prefixes, 369 NAS1611 and NAS1612 part numbers by Conquest's size reading, 369 AS568 sizes (written AS568-214, 2-214 or 214, or typed as inside diameter x cross-section in inches), 358 ISO 3601-1 metric sizes (by code, such as C0450, or by inside diameter x cross-section in millimeters, written 55 x 2, 55 mm x 2 mm or 55MM ID x 2MM CS) and 767 NSNs that DLA's FLIS lists for 627 of the part numbers, as the part pages print them. 655 of the part numbers have a page of their own; the rest open their family page.
| Prefix | Example | AS568 size of the example | Document | Compound | Part numbers on file |
|---|---|---|---|---|---|
| MS28775 | MS28775-214 | AS568-214 nominal | MIL-PRF-25732 (MS28775 part drawing) | NBR | 346 |
| M83461/1 | M83461/1-214 | AS568-214 | MIL-P-83461/1 | NBR | 346 |
| M83248/1 | M83248/1-214 | AS568-214 | MIL-R-83248/1 (Class 1) | FKM | 346 |
| M83248/2 | M83248/2-214 | AS568-214 | MIL-R-83248/2 (Class 2) | FKM | 346 |
| AS3209 | AS3209-214 | AS568-214 | SAE AS3209 (AMS7276) | FKM | 346 |
| M83485/1 | M83485/1-214 | AS568-214 | MIL-R-83485 | FKM, low-temperature grade | 346 |
| M25988/1 | M25988/1-214 | AS568-214 | MIL-DTL-25988/1 | FVMQ | 346 |
| M25988/2 | M25988/2-214 | AS568-214 | MIL-DTL-25988/2 | FVMQ | 346 |
| M25988/3 | M25988/3-214 | AS568-214 | MIL-DTL-25988/3 | FVMQ | 346 |
| M25988/4 | M25988/4-214 | AS568-214 | MIL-DTL-25988/4 | FVMQ | 346 |
| MS29513 | MS29513-214 | AS568-214 nominal | MIL-P-5315 (MS29513 part drawing) | NBR | 313 |
| AS3582 | AS3582-214 | AS568-214 | SAE AS3582 (AMS3304) | VMQ silicone | 346 |
| AS9386 | AS9386-214 | AS568-214 nominal | SAE AS9386 (AMS7267) | VMQ silicone | 346 |
| M83461/2 | M83461/2-904 | AS568-904 | MIL-P-83461/2 | NBR | 20 |
| AS3208 | AS3208-04 | AS568-904 | SAE AS3208 (AMS7276) | FKM | 20 |
| MS29512 | MS29512-04 | AS568-904 nominal | MIL-P-5315 (MS29512 boss drawing) | NBR | 20 |
| AS9385 | AS9385-04 | AS568-904 nominal | SAE AS9385 (AMS7267) | VMQ silicone | 20 |
| NAS1611 | NAS1611-214 | AS568-214 (Conquest’s reading) | NAS1611 (AIA National Aerospace Standard) | EPDM | 349 |
| NAS1612 | NAS1612-04 | AS568-904 (Conquest’s reading) | NAS1612 (AIA National Aerospace Standard) | EPDM | 20 |
The NAS1611 and NAS1612 rows are Conquest's size reading (2026-10-11), not a register record: NAS1611-XXX at the AS568-XXX size and NAS1612-YY at the AS568-9YY boss size. The AIA and DLA records on file give neither standard an AS568 size and do not define the -A suffix; by the same reading the suffix marks a part made to NAS1613 Revision 6 and its absence a part made to Revision 2, and it stays on the quote as typed.
| Printed form | Read as | Records on file |
|---|---|---|
| AS28775-XXX | MS28775-XXX | DoD canceled the MS28775 drawing on 2000-09-29, and SAE-AS28775 superseded it with the same part numbers (DLA ASSIST ident 41724, read 2026-10-04). |
| AS83461/1-XXX | M83461/1-XXX | The family page prints both forms for the same part number. |
| AS29513-XXX | MS29513-XXX | DoD canceled the MS29513 drawing on 2001-03-01, and SAE-AS29513 superseded it with the same part numbers (DLA ASSIST ident 41788, read 2026-09-27). |
| MS9386-XXX | AS9386-XXX | DoD canceled the MS9386 drawing on 1999-10-15, and SAE-AS9386 superseded it with the same part numbers (DLA ASSIST ident 37861, read 2026-09-27). |
| AS29512-XXX | MS29512-XXX | DoD canceled the MS29512 drawing on 2001-03-01, and SAE-AS29512 superseded it with the same part numbers (DLA ASSIST ident 41787, read 2026-09-27). |
| MS9385-XXX | AS9385-XXX | DoD canceled the MS9385 drawing on 1999-12-29, and SAE-AS9385 superseded it with the same part numbers (DLA ASSIST ident 37860, read 2026-09-27). |
| Prefix | What the records say |
|---|---|
| NAS1613 | NAS1611, NAS1612 and NAS1613 are National Aerospace Standards, published and sold by the Aerospace Industries Association (AIA), which is why they behave differently from every MIL and SAE family on this site. |
| MS9068 | One manufacturer's aerospace cross-reference (Freudenberg, July 2024, read 2026-09-27) lists MS9068 against AMS3304 and holds its parts over 0.500 in ID to a tight tolerance; MS9068's document status is not verified here. |
| AS83248/1 | AS83248/1-XXX and M83248/1-XXX use the same three-digit dash on the same AMS7276 material. |
| MIL-R-83248 | MIL-R-83248 is cancelled, and the compounds are now SAE-AMS7276 (70 to 80) and SAE-AMS7259 (85 to 95). |
| MIL-R-83248/1 | Fluorocarbon (FKM) at Class 1, 75 hardness, as the MIL-R-83248/1 title prints it. |
| AMS-R-83248 | SAE's parallel material document, AMS-R-83248, is cancelled; its last revision is A, of 2005. |
| AS83248/2 | The /2 sheet's record names SAE-AS3581, and SAE also issued AS83248/2 (2014), which DoD adopted the same day. |
| AS3581 | If the print needs 90 hardness, the family's /2 sheet and AS3581 on AMS7259 cover it. |
| AMS7276 | DLA ASSIST records MIL-R-83248 cancelled on 2001-06-21 and names four SAE successors in its title: AMS7276, AMS7259, AMS3216 and AMS3218. |
| MIL-P-83461 | M83461/1-XXX specifies a nitrile (NBR) O-ring for petroleum hydraulic fluid with improved performance over the MS28775 family, in the AS568 size the dash names; the governing MIL-P-83461 and its size sheet MIL-P-83461/1 were cancelled on 2003-10-01 and superseded by SAE-AMS-P-83461 (the material, issued 1998) and SAE-AS83461/1 (the drawing, current at revision C, revised in October 2016 and reaffirmed on 2021-11-08, titled M83461 O-ring molded from AMS-P-83461 rubber). |
| MIL-P-83461/1 | M83461/1-XXX specifies a nitrile (NBR) O-ring for petroleum hydraulic fluid with improved performance over the MS28775 family, in the AS568 size the dash names; the governing MIL-P-83461 and its size sheet MIL-P-83461/1 were cancelled on 2003-10-01 and superseded by SAE-AMS-P-83461 (the material, issued 1998) and SAE-AS83461/1 (the drawing, current at revision C, revised in October 2016 and reaffirmed on 2021-11-08, titled M83461 O-ring molded from AMS-P-83461 rubber). |
| MIL-P-83461/2 | The slash sheet on this family is the size sheet: /1, MIL-P-83461/1, covers the standard AS568 sizes, and /2, MIL-P-83461/2 (30 January 1991), covers the straight-thread tube fitting boss sizes, AS568-901 to -932, written with the same three-digit dash; M83461/2-903 is the sheet's own example. |
| AMS-P-83461 | M83461/1-XXX specifies a nitrile (NBR) O-ring for petroleum hydraulic fluid with improved performance over the MS28775 family, in the AS568 size the dash names; the governing MIL-P-83461 and its size sheet MIL-P-83461/1 were cancelled on 2003-10-01 and superseded by SAE-AMS-P-83461 (the material, issued 1998) and SAE-AS83461/1 (the drawing, current at revision C, revised in October 2016 and reaffirmed on 2021-11-08, titled M83461 O-ring molded from AMS-P-83461 rubber). |
| AMS-P-83461/1 | M83461/1-XXX is the AS568-XXX size; the same dash on the AMS-P-83461/1 callout is the same size. |
| AMS-P-83461/2 | DLA ASSIST records the /2 sheet as canceled on 2003-10-01, with future acquisitions referred to SAE AMS-P-83461/2, whose adoption DoD withdrew on 2010-01-20 for SAE AS83461/2, Active (idents 71937, 213940 and 277054, read 2026-10-04). |
| AS83461/2 | DLA ASSIST records the /2 sheet as canceled on 2003-10-01, with future acquisitions referred to SAE AMS-P-83461/2, whose adoption DoD withdrew on 2010-01-20 for SAE AS83461/2, Active (idents 71937, 213940 and 277054, read 2026-10-04). |
| MIL-PRF-25732 | MIL-P-25732 is one government record that changed prefix twice, to MIL-DTL-25732 and then MIL-PRF-25732; its revision E is dated 2024-03-08 and DLA ASSIST lists it as inactive for new design. |
| MIL-P-25732 | MIL-P-25732 is one government record that changed prefix twice, to MIL-DTL-25732 and then MIL-PRF-25732; its revision E is dated 2024-03-08 and DLA ASSIST lists it as inactive for new design. |
| MIL-DTL-25732 | MIL-P-25732 is one government record that changed prefix twice, to MIL-DTL-25732 and then MIL-PRF-25732; its revision E is dated 2024-03-08 and DLA ASSIST lists it as inactive for new design. |
| AMS-P-25732 | SAE issued its parallel material document, AMS-P-25732, in 1998 and cancelled it in August 2003 at revision A. |
| MS28778 | There is no two-digit boss variant in this family; the boss gasket callout is MS28778. |
| MIL-R-83485 | MIL-R-83485 is cancelled; its SAE successors, the material document AMS-R-83485 and the sizes-and-tolerances sheet AMS-R-83485/1, were cancelled in 2014 and 2015, and one manufacturer's 2024 cross-reference now lists the same part against SAE-AMS7287 (fluorocarbon 70 to 80, low-temperature sealing). |
| MIL-R-83485/1 | A print that reads M83485/1 is quoted against MIL-R-83485/1, the callout on the print. |
| AMS-R-83485 | MIL-R-83485 is cancelled; its SAE successors, the material document AMS-R-83485 and the sizes-and-tolerances sheet AMS-R-83485/1, were cancelled in 2014 and 2015, and one manufacturer's 2024 cross-reference now lists the same part against SAE-AMS7287 (fluorocarbon 70 to 80, low-temperature sealing). |
| AMS-R-83485/1 | MIL-R-83485 is cancelled; its SAE successors, the material document AMS-R-83485 and the sizes-and-tolerances sheet AMS-R-83485/1, were cancelled in 2014 and 2015, and one manufacturer's 2024 cross-reference now lists the same part against SAE-AMS7287 (fluorocarbon 70 to 80, low-temperature sealing). |
| MIL-DTL-83485 | Two things to keep straight: 83485 is a fluorocarbon, not a fluorosilicone (the fluorosilicone family is 25988), and MIL-DTL-83485 does not exist on DLA ASSIST. |
| AMS7287 | SAE had issued AMS7287, a fluorocarbon 70 to 80 document for low-temperature sealing, in 2012, and revised it to A on 2022-09-08, and one manufacturer's 2024 cross-reference now lists AMS7287 for the M83485/1 part, with AMS-R-83485 and MIL-R-83485 as the previous documents. |
| MIL-R-25988 | M25988/X-XXX is a fluorosilicone (FVMQ) O-ring for oil and fuel service under MIL-DTL-25988, the same document as MIL-R-25988. |
| MIL-DTL-25988 | M25988/X-XXX is a fluorosilicone (FVMQ) O-ring for oil and fuel service under MIL-DTL-25988, the same document as MIL-R-25988. |
| MIL-DTL-25988/1 | Fluorosilicone (FVMQ), Class 1 Grade 70, under MIL-DTL-25988/1, an oil and fuel resistant document. |
| AMS-R-25988 | SAE cancelled its parallel AMS-R-25988 in August 2017 at revision A, and DoD's notice of 2018-01-02 withdrew its adoption, naming MIL-DTL-25988 as the superseding document; SAE then revised AMS-R-25988 to B in June 2023, which SAE Mobilus shows as its current revision. |
| MIL-P-5315 | The governing MIL-P-5315 was cancelled on 2002-02-28 in favor of SAE-AMS-P-5315 (current at revision C of 2022-08-05), and the drawings are current as SAE-AS29513C and SAE-AS29512C, both revised in October 2016 and reaffirmed on 2021-11-09. |
| AMS-P-5315 | A print that reads MS29513 or MS29512 is therefore quoted against AS29513 or AS29512 for the drawing and AMS-P-5315 for the material. |
| AMS3304 | AS3582-XXX is a silicone (VMQ) O-ring made from AMS3304 material, the heat and weather resistant silicone rubber in the 65 to 75 hardness class, in the AS568 size the dash names. |
Every figure and status comes from the files this site's part and size pages print: the AS568 size chart, the mil-spec register (DLA ASSIST and SAE Mobilus records), the ISO 3601-1 list (Precision Polymer Engineering, 'ISO 3601 O-ring Sizes' reference table (read 2026-09-06)) and the NSNs the part pages print from DLA's FLIS (read 2026-10-08). The prefixes and forms are arranged here by Conquest; no standard's text or table is reproduced. Your drawing governs.
Frequently asked
Is a 2-214 the same size as an AS568-214?
In size, yes. A 2- in front of a three-digit dash number is a maker's catalog form of the AS568 size with that dash number; the compound code that follows it names that maker's own rubber, which is what makes the part one maker's product.
Does the same dash number mean the same part?
No. The dash number carries the size and the document carries the compound. MS28775-214 (nitrile), M83248/1-214 (fluorocarbon) and M25988/1-214 (fluorosilicone) name one nominal size in three rubbers, so a size match alone never settles a cross, and whether one part may replace another is the decision of whoever owns the print.
Where do the figures come from?
The AS568 dimensions and tolerances are this site's AS568 size chart. The documents, compounds and statuses are the mil-spec register on this site, read from DLA ASSIST and SAE Mobilus, with the read date in each record. The metric rows are the ISO 3601-1 list on this site (Precision Polymer Engineering, 'ISO 3601 O-ring Sizes' reference table (read 2026-09-06)). The NSNs are the ones the part pages print from DLA's FLIS (read 2026-10-08). The tool reads the same files the part and size pages print; nothing is typed by hand.
Can I type a size instead of a part number?
Yes. Type the inside diameter and the cross-section, in millimeters (55 x 2, 55 mm x 2 mm, 55MM ID x 2MM CS, 55,0 x 2,0) or inches (1.234 x .139, 1-1/4 x 3/32), with or without the ID and CS labels; an outside diameter is converted (OD = ID + 2 x W). A metric size is read against the ISO 3601-1 list on this site and an inch size against the AS568 table. When the size is not a listed size, the tool shows the listed sizes nearest to it by both dimensions with the difference in each; a nearest size is a different size, and the print governs.
What if my part number is not found?
Send it exactly as your print reads it, with the drawing revision and the quantity, through the quote form. A Conquest representative reads every request and replies within one business day.
Related pages
- O-ring part number cross-reference guide: crossing the size and the material
- Mil-spec O-ring index: every family, its documents and their status
- AS568 size chart and the ISO 3601-1 metric sizes
- O-ring materials: the compound families the documents name
- O-rings
Orders are handled under Conquest Seal's AS9100D quality management system, whose certificate scope includes distribution.
Part number not on file?
Send it exactly as your print reads it, with the drawing revision and the quantity. A Conquest representative reads every request and replies within one business day.
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