... of viton O Ring:1. Materials: can be NBR, Viton, EPDM, SI, HNBR, BUNA, MVQ, ACM, FLS, CR, SBR, SI, BR ... tolerance: exactly upon your request or standard tolerance.5. Color: black, transparent, green, red, yellow, grey, purple, pink, etc. or upon ... time: 1~3 weeks.8. Small order quantity is welcomed. black viton o ring for valve