PartsTable
Technical Data Sheet
Download PDF

S278DT12 — STRAP,RETAINING

✓ Government record, cited
— · ORING SEAL
PRODUCT OVERVIEW

S278DT12: STRAP,RETAINING.

The STRAP,RETAINING is a the manufacturer industrial component. Key specifications include cushion: INCLUDED, material: ALUMINUM ALLOY 2024 AND ALUMINUM ALLOY 1230 LOCATION NOT OTHERWISE SPECIFIED, mounting_pad: NOT INCLUDED, overall_width: 0.500 INCHES NOMINAL IN, overall_length: 2.098 INCHES NOMINAL IN, style_designator: SADDLE ARCH. This part is cataloged in the U.S.

Government catalog under NSN 5340-00-916-4752, indicating validated use in U.S. government and defense logistics supply chains. Available through authorized enterprise resellers and TPM (Third Party Maintenance) channels.

Verify compatibility with your specific system configuration before ordering.

WHERE IT FITS
S278DT12
NSN: 5340-00-916-4752
FSC: 5340 — Hardware, Commercial
CAGE: 18076 — UMPCO, INC. DBA UMPCO INC (USA)
SPECIFICATIONS
cushionINCLUDED
materialALUMINUM ALLOY 2024 AND ALUMINUM ALLOY 1230 LOCATION NOT OTHERWISE SPECIFIED
mounting_padNOT INCLUDED
overall_width0.500 INCHES NOMINAL IN
overall_length2.098 INCHES NOMINAL IN
style_designatorSADDLE ARCH
material_thickness0.040 INCHES NOMINAL IN
mounting_hole_size0.204 INCHES NOMINAL IN
inside_diameter/arch_length0.735 INCHES MINIMUM AND 0.765 INCHES MAXIMUM IN
material_document_and_classificationAMS 3651 ASSN STD SINGLE MATERIAL RESPONSE CUSHIONING
distance_between_mounting_hole_centers1.660 INCHES NOMINAL IN
distance_between_base_and_inside_of_arch0.825 INCHES MINIMUM AND 0.855 INCHES MAXIMUM IN
NSN5340-00-916-4752
COMPONENT DIAGRAM
O-RING / SEAL — MATERIAL DETERMINES APPLICATION ID: — CROSS-SECTION CS: — SPECIFICATION Material: — Durometer: — Temp: — PN: S278DT12 MFR: OEM ⚠ VERIFY BEFORE ORDERING Wrong material = failure. Viton for oil/fuel, EPDM for water/steam, Buna-N for general purpose, Silicone for food-grade. Chemical incompatibility causes swelling, brittleness, or rapid degradation ✓ BROKER TIP Durometer (hardness) affects sealing pressure tolerance. Higher Shore A = harder = higher pressure. Standard durometer is 70A — verify if application requires different hardness PARTSTABLE TECHNICAL DRAWING — NOT TO SCALE
KEY FEATURES
•
MOUNTING HOLE SIZE: 0.204 INCHES NOMINAL IN
•
DISTANCE BETWEEN MOUNTING HOLE CENTERS: 1.660 INCHES NOMINAL IN
•
MOUNTING PAD: NOT INCLUDED
•
STYLE DESIGNATOR: SADDLE ARCH
•
MATERIAL DOCUMENT AND CLASSIFICATION: AMS 3651 ASSN STD SINGLE MATERIAL RESPONSE CUSHIONING
TECHNICAL CHARACTERISTICS
MOUNTING HOLE SIZE0.204 INCHES NOMINAL IN
DISTANCE BETWEEN MOUNTING HOLE CENTERS1.660 INCHES NOMINAL IN
MOUNTING PADNOT INCLUDED
STYLE DESIGNATORSADDLE ARCH
MATERIAL DOCUMENT AND CLASSIFICATIONAMS 3651 ASSN STD SINGLE MATERIAL RESPONSE CUSHIONING
MATERIAL DOCUMENT AND CLASSIFICATIONQQ-A-250/5, T4 FED SPEC SINGLE MATERIAL RESPONSE LOCATION NOT OTHERWISE SPECIFIED
OVERALL LENGTH2.098 INCHES NOMINAL IN
OVERALL WIDTH0.500 INCHES NOMINAL IN
MATERIAL THICKNESS0.040 INCHES NOMINAL IN
CUSHIONINCLUDED
OTHER ITEMS IN FSC 5340 — Hardware, Commercial
Items in the same Federal Supply class. No interchangeability or substitution relationship is implied.
5340-00-000-0068 5340-00-000-0132 5340-00-000-8150 5340-00-001-1251 5340-00-001-1264 5340-00-001-1265 5340-00-001-1266 5340-00-001-1275
SUBSTITUTES & CROSS-REFERENCES 2
C641D12TReference document
Same NSN cross-reference
Reference document — Vendor item drawing reference
978D12TSame NSN cross-reference
Same NSN cross-reference
Also cataloged under this NSN
LIFECYCLE
NSN statusActive· U.S. Government catalog
Acquisition advice: Insurance item — stocked against contingency demandNo demilitarization required
Ready to buy S278DT12?
Compare prices from verified sellers on eBay
Buy on eBay →
As an eBay Partner, PartsTable may earn a commission. Your price is not affected.
FREQUENTLY ASKED QUESTIONS
What is S278DT12?
S278DT12 is a STRAP,RETAINING.
What parts can replace S278DT12?
There are 2 known substitutes for S278DT12: C641D12T, 978D12T. Substitute compatibility should be verified for your specific system.
What is the NSN for S278DT12?
S278DT12 is cataloged in the U.S. Government catalog under NSN 5340-00-916-4752. This indicates validated use in U.S. government and defense supply chains.
Community Feedback
Leave a Comment
Comments are reviewed before appearing. You will receive an email to verify before your comment appears.

Request a Quote — S278DT12

✓ PartsTable — the parts reference. Every fact cited to its source.
PartsTable Design LLC · partstable.com
U.S. Government catalog: edition PUBLOGDVD v12.0.0 (OCT 2026), edition date 2026-10-01, retrieved 2026-10-18.
PartsTable commercial catalog: edition Unified commercial catalog snapshot through 2026-09-28, edition date not on file, retrieved 2026-09-28.