407pcs O-Ring Assortment 407pcs O-Ring Assortment1. Materials: NBR,also can be NR, HNBR, MVQ, ACM, FLS, CR, SBR, SI, BR, IR, EPDM, IIR, PU,E/A, ECO, CSM, VITON, FKM, FPM, etc.2. Characteristics: oil proof, aging resistant, heat resistant, wear resistant, chemical resistant, anti-corrosion, etc. 3. Hardness: 30~90 shore A or IRHD as your request, tolerance is ± 5 shore A, and can be ±3 shore A for ...