Mil-spec part number, M83485/1 family

M83485/1-243 O-ring: fluorocarbon (FKM), low-temperature grade, the AS568-243 size

M83485/1-243 is the AS568-243 O-ring size, 4.109 in (104.37 mm) inside diameter by 0.139 in (3.53 mm) cross-section, in fluorocarbon (FKM), low-temperature grade procured to MIL-R-83485. The DLA ASSIST and SAE Mobilus records read: Canceled (MIL-R-83485). The dash sets the size and the document sets the compound, so an AS568-243 in another compound is not the same part as M83485/1-243. Send the designator exactly as the print reads and we quote it against that document.

Inside diameter
4.109 in104.37 mm, +/- 0.028 in
Cross-section
0.139 in3.53 mm, +/- 0.004 in
AS568 size
AS568-2432xx series
Document status
CanceledMIL-R-83485
Request a quote for M83485/1-243 M83485/1 family AS568-243 size page
OD 4.387 in (111.43 mm) ref ID 4.109 in (104.37 mm) W 0.139 in (3.53 mm) section A-A M83485/1-243 AS568, inch authoritative
Dimensioned from the AS568 table for AS568-243, the size M83485/1-243 names. Not to scale.

Part facts

M83485/1-243: document, status, polymer and size
ItemValue
Part numberM83485/1-243
NSN5331-01-412-3637 (DLA FLIS, read 2026-10-08)
Procured toMIL-R-83485
SAE documentSAE AMS-R-83485; SAE revised it to A and cancelled it in May 2014 (AMSR83485A); for the O-ring sheet, MIL-R-83485/1, DLA ASSIST names SAE AMS-R-83485/1, and SAE cancelled it in June 2015 (AMSR83485/1A)
StatusCanceled (MIL-R-83485)
Base polymerFluorocarbon (FKM), low-temperature grade
AS568 sizeAS568-243
CAD for the AS568-243 sizeAS568-243 STEP 3D solid, AS568-243 DXF 2D drawing, AS568-243 PDF dimensioned drawing; generated from the AS568 nominal dimensions, so verify against your drawing
Back-up ringsMS28774-243 (single-turn scarf-cut PTFE) or MS27595-243 (continuous PTFE), both procured to SAE AS8791; both drawings are inactive for new design
M83485/1-243: dimensions and tolerances from the AS568 table
DimensionValueTolerance
Inside diameter (ID)4.109 in 104.37 mm+/- 0.028 in (0.71 mm)
Cross-section (W)0.139 in 3.53 mm+/- 0.004 in (0.10 mm)
Outside diameter (reference)4.387 in 111.43 mmderived: ID + 2 x W

Millimeter values are converted from the inch table. M83485/1 is a low-temperature fluorocarbon, not a fluorosilicone; one manufacturer's aerospace cross-reference (Freudenberg, July 2024, read 2026-09-27) lists it against AMS7287. Both SAE successors DLA ASSIST names are cancelled: it records MIL-R-83485 and its O-ring sheet, MIL-R-83485/1, as canceled on 2002-10-23 and superseded by SAE-AMS-R-83485 and SAE-AMS-R-83485/1 (idents 33839 and 33840, read 2026-09-28), and SAE cancelled AMS-R-83485 in May 2014 (AMSR83485A) and AMS-R-83485/1 in June 2015 (AMSR83485/1A) (SAE Mobilus, read 2026-09-27 and 2026-09-28).

Same nominal size, other documents

Other part numbers for the AS568-243 size

These part numbers name the AS568-243 nominal size under a different document, so each one is a different compound. They are not interchangeable with M83485/1-243 unless the print or the buyer's engineering allows it. At this size the family sheets for MS28775-243, MS29513-243 and AS9386-243 hold a tighter inside-diameter tolerance than AS568.

Part standards that call out the AS568-243 nominal size
Part numberDocumentPolymerStatus
MS28775-243MIL-PRF-25732 (MS28775 part drawing)NBRInactive (MIL-PRF-25732); AS28775A current
M83461/1-243MIL-P-83461/1NBRCanceled; AS83461/1C current
M83248/1-243MIL-R-83248/1 (Class 1)FKMCanceled; AS3209C stabilized; AS83248/1A current
M83248/2-243MIL-R-83248/2 (Class 2)FKMCanceled; AS3581A stabilized; AS83248/2A current
AS3209-243SAE AS3209 (AMS7276)FKMAS3209C stabilized
M25988/1-243MIL-DTL-25988/1FVMQActive
M25988/2-243MIL-DTL-25988/2FVMQActive
M25988/3-243MIL-DTL-25988/3FVMQActive
M25988/4-243MIL-DTL-25988/4FVMQActive
MS29513-243MIL-P-5315 (MS29513 part drawing)NBRCanceled (MIL-P-5315); AS29513C current
AS3582-243SAE AS3582 (AMS3304)VMQ siliconeAS3582 current
AS9386-243SAE AS9386 (AMS7267)VMQ siliconeAS9386B current

The base polymer

M83485/1-243 is fluorocarbon (FKM), low-temperature grade. The Parker® O-Ring Handbook ORD 5700 range published for the FKM family (section 2.2) is -26 C to 204 C. That is the polymer family's range, not this document's requirement; the compound sheet for the qualified grade governs.

Material page: Fluorocarbon (FKM), low-temperature grade O-rings. Every document in the family: M83485/1 O-rings.

Nearby M83485/1 part numbers

Part numberID inID mmW inW mm
M83485/1-2292.35959.920.1393.53
M83485/1-2302.48463.090.1393.53
M83485/1-2363.23482.140.1393.53
M83485/1-2434.109104.370.1393.53
← M83485/1-236M83485/1 family

Frequently asked

What is the AS568 equivalent of M83485/1-243?

M83485/1-243 is the AS568-243 size: 4.109 in (104.37 mm) inside diameter by 0.139 in (3.53 mm) cross-section. The dash sets the size; MIL-R-83485 sets the fluorocarbon (FKM), low-temperature grade compound. An AS568-243 ring in any other compound has the same dimensions but is not the same part as M83485/1-243.

What is the NSN for M83485/1-243?

DLA's public FLIS data lists M83485/1-243 on NSN 5331-01-412-3637 (read 2026-10-08). An NSN is the federal catalog's number for the item; your contract or print decides what is ordered.

Is MIL-R-83485 still active?

The document status reads: Canceled (MIL-R-83485). It comes from the DLA ASSIST and SAE Mobilus records listed under Sources, with the date each was read. A canceled or inactive MIL document can still be the one a print calls out, and your print decides which you order to. The SAE document, SAE AMS-R-83485, is not a current alternative: SAE revised it to A and cancelled it in May 2014 (AMSR83485A). Nor is SAE AMS-R-83485/1, the successor DLA ASSIST names for the O-ring sheet, MIL-R-83485/1: SAE cancelled it in June 2015 (AMSR83485/1A).

How do I order M83485/1-243?

Send the designator exactly as the print reads, with its revision, any suffix letter, the quantity and the paperwork the order needs. M83485/1-243 is quoted and supplied against MIL-R-83485, in the compound the print calls out, with a certificate of conformance with every order. When the print calls out a QPL-listed specification, the finished molded O-ring, or the material it is molded from, comes from a manufacturer listed on that QPL; Conquest supplies it and is not itself on any QPL. A Conquest representative replies within one business day.

Sources

DLA ASSIST document details, ident 33840 (MIL-R-83485/1), read 2026-09-24; DLA ASSIST Document ID searches for MIL-R-83485 (two records, the base document and sheet /1) and MIL-DTL-83485 (no record), read 2026-09-28; SAE Mobilus: AMSR83485A (revised and cancelled May 2014) and AMS7287A (revised 2022-09-08), read 2026-09-27; SAE Mobilus: AMSR83485/1A (issued March 2001, cancelled June 2015), read 2026-09-28; the NSNs from DLA's public FLIS data (PUB LOG Reference, Identification and Characteristics files, updated 2026-10-01, read 2026-10-08); an NSN is the federal catalog's stock number for an item and does not name or approve a supplier; SAE Mobilus: AMSR83485/1A (cancelled June 2015), read 2026-09-28; DLA ASSIST Document ID search for MIL-R-83485 (idents 33839 and 33840: the base document and its O-ring sheet /1, both canceled 2002-10-23, superseded by SAE-AMS-R-83485 and SAE-AMS-R-83485/1), read 2026-09-28; AS568 dimensions from the Parker O-Ring Handbook ORD 5700, 2021 printing, section IX, AS568 size tables (Series 2-XXX and 3-XXX), pages 9-2 to 9-11, read 2026-10-13; the dash-to-size mapping from the Freudenberg Sealing Technologies, Aerospace Part and Material Cross-Reference brochure (July 2024), pages 3 and 4, read 2026-10-13; the other part numbers' dash-to-size mapping and tolerance note from the MS28775 Revision E sheet (1984-03-23, read 2026-10-04), MS29513 Revision C sheet (1966-09-16, read 2026-09-27) and MS9386 Revision B sheet (1975-01-17, read 2026-09-27), DLA ASSIST; the other part numbers' statuses from DLA ASSIST document details, idents 18115 (MIL-PRF-25732), 33814 (MIL-P-83461/1), 33574 (MIL-R-83248/1), 33575 (MIL-R-83248/2), 18214 (MIL-DTL-25988/1), 18215 (MIL-DTL-25988/2), 18216 (MIL-DTL-25988/3), 18217 (MIL-DTL-25988/4) and 5334 (MIL-P-5315), read 2026-09-24; SAE Mobilus current-revision records AS83248/2A, read 2026-09-28; AS83461/1C, AS3209C, AS83248/1A, AS3581A, AS29513C, AS3582 and AS9386B, read 2026-09-27; AS28775A, read 2026-09-25; the MIL-R-83248/1A cancellation notice (Notice 5, 2008-07-24), DLA ASSIST, read 2026-09-29; the SAE-AS83248/2 adoption record, DLA ASSIST ident 286631, read 2026-09-28; the polymers from the Parker O-Ring Handbook ORD 5700A/US, section 8, pages 8-2, 8-4 and 8-5 (read 2026-09-24); the back-up ring pairing and cut styles from the same handbook, section 6, pages 6-8 and 6-9 (read 2026-09-25); SAE AS8791 and the drawings' status from the MS28774M and MS27595E drawings, DLA ASSIST (read 2026-09-28); Parker O-Ring Handbook ORD 5700A/US, section 2.2, for the polymer family range (read 2026-09-14). Facts are stated in our own words and arrangement; no standard's text or table is reproduced.

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Orders are handled under Conquest Seal's AS9100D quality management system, whose certificate scope includes distribution.

Need M83485/1-243 with certification?

Send the part number as the print reads it, the quantity and the paperwork the order needs. A Conquest representative replies within one business day. A person answers (714) 632-9830, Pacific business hours.

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