... , FLS, CR, SBR, SI, BR, IR, EPDM, IIR, butyl, PU, E/A, ECO, CSM, VITON, FKM, FPM, etc.2. Characteristics: good physical ... chemical properties standards o ring. 3. Hardness: 30~90 shore A or IRHD as your request, tolerance is ± 5 shore ... A, and can be ±3 shore A for special products o-ring. 4. Size tolerance ...