279pcs O-Ring Assortment 279pcs O-Ring Assortment1. Materials: NBR,also can be NR, HNBR, ... MVQ, ACM, FLS, CR, SBR, SI, BR, IR, EPDM, IIR, PU,E/A ... 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 special products.4. Size tolerance: ...