... for different rubber, likes viton , NBR, CR, etc x-ring, o-ring, square ring,,,etc for new sizes or new models ... it according your required.hydraulic sealing items.backups , dowty seals, u seals,o rings, wipers, oil seals, piston seals, v packings, rod ... rings, piston cups,,,,etc.O-Ring (NBR 72 Shore)O-Ring (NBR 88 Shore)O-Ring (FKM 80 Shore)O-Ring (EPDM 70 Shore ...