The M83248-1-128 is a military-specification fluorocarbon (FKM, Viton®-type) O-ring used for high-performance sealing in aircraft fuel, oil, and hydraulic systems. It is manufactured under the MIL-R-83248 / M83248 standard, which defines strict requirements for material quality, dimensional accuracy, and resistance to temperature and fluids.

Made from fluorocarbon rubber (FKM), this O-ring provides excellent resistance to aviation fuels (Avgas, Jet A), turbine oils, and petroleum-based hydraulic fluids, while maintaining sealing integrity under high temperature and compression conditions. It is commonly used in engine accessories, fuel system fittings, valves, and aircraft hydraulic assemblies.

Compared to standard nitrile seals, the M83248 series offers higher heat resistance, lower compression set, and improved chemical stability, making it suitable for flight-critical applications.

Key features include:

Proponent part number: M83248-1-128
Military specification: MIL-R-83248 / M83248 series
Material: Fluorocarbon rubber (FKM / Viton® type)
Designed for aircraft fuel, oil, and hydraulic sealing
High temperature resistance (up to ~400°F / 204°C typical range) 
Excellent resistance to aviation fuels and turbine oils
Low compression set for long-term sealing performance
Used in engine, fuel system, and hydraulic components
Standardized aerospace interchange part
Suitable for static and dynamic sealing applications
High reliability in harsh aerospace environments