... CR, SBR, SI, BR, IR, EPDM, IIR, butyl, PU, E/A, ECO, CSM, VITON, FKM, FPM, etc.2. Characteristics: good ... standards o ring. 3. Hardness: 30~90 shore A or IRHD as your request, tolerance is ± 5 ... . 11. Production lead time: 1~2 weeks. 12. Small order quantity is welcomed. ------------------------------------------------standards o ring------------------------------------------------- Thank you ...