Oil Seals are used to prevent oil leakage from rotary shaft and housing clearance. It has a flexible lip that rubs against a shaft or housing to prevent leakage or ingress of fluid and dirt. Seal Selection is based on shaft diameter , housing bore diameter and width, shaft speed, working temperature, fluid, pressure differential and service conditions. Common configurations include single lip, double lip, triple lip, and four or more lips.

Rubber sealing element or lip material choices for oil seals include : Nitrile Rubber (NBR), Acrylic Rubber (ACM), Silicon Rubber (VMQ), Fluorocarbon Rubber (Viton/FKM), Ethylene Propylene Rubber (EPDM), Tetrafluoroethylene Resin (PTFE). To resist wear, the compound durometer (hardness) is typically 70 to 85 shore A.