... highest valve with competitive in price.All materials are import.Various of O-ring provide for you. The nbr O-ring are made ... materials,such as Silicone O-ring,NBR O-ring,HNBR O-ring,EPDM O-ring,CR O-ring,FPM O-ring,PU O-ring.Different material of ... -proof,oil-proof,abrasion proof and so on.The O-rings are made in different sizes.The smallest size is 0.74 ...