... o-ring. 4. Size tolerance: exactly upon your request or standard tolerance. 5. Color: black rubber seal gasket, transparent, green, red, yellow, grey, purple, pink rubber seal gasket ... , NSF, KTW, WRAS, LFGB, etc. 8. Applications: automobile rubber seal gasket, electrical appliance, mechanical rubber seal gasket, industrial, construction, household, medical and other fields. 9. QC ...