... By Client's demond 3.Many standards available Product: glow in the dark o ring O ring is a kind of sealing ... . O-Ring is good at both in static seal and dynamic seal, main material contains: NR, CR, NBR, SBR, VITON, SILICON, HNBR ... , PU etc.Item nameO ringMaterialNBR,HNBR,EPDM,SILICONE,VITON,NR,CR,SBR,PUHardness30-100 shore ASizeCustomized/standard/nonstandardColorRed, Black, White, Clear ...