Dear Mr.Tian Please find below O rings specification and let me know can you manufacture it ?Material : RUBBER, FLUOROCARBON, HIGH TEMPERATURE, FLUID AND COMPRESSION SET RESISTANT (MIL-R-83248) Diameter Range 9MM-280MM Key Dimensions Diameter and high Key Tolerances 0.05MM for diameter Manufacturing Process Compounding Fabric Forming sulfuration Post-curingWait your early reply.