AMS-R-83485 FKM elastomers have superior low-temperature performance of 25°F.

AMS-R-83485 is from Amendment 3 of MIL-R-83485, with minor edits, and has been adopted as an SAE standard. However, the spec has since been superseded by:

• Type I: AMS 7287—Fluorocarbon Elastomer (FKM) High Temperature/HTS Oil Resistant/Fuel Resistant Low Compression Set/70 to 80 Hardness, Low-TemperatureLow Temperature Tg -22 °F (-30 °C), for Seals in Oil/Fuel/Specific Hydraulic Systems
• Type II: AMS 3384—Rubber, Fluorocarbon Elastomer (FKM) 70 to 80 Hardness, Low Temperature Sealing Tg -22 °F (-30 °C) For Elastomeric Shapes or Parts in Gas Turbine Engine Oil, Fuel and Hydraulic Systems

Please note: The information outlined above is to be used as a reference for AMS-R-83485. Please refer to SAE International for full details and the most current revision.