Oil seals are used for sealing purposes, mainly to prevent oil and gas leakage, hence the name "oil seal." The standard specification for most oil seals is O-shaped, and due to its shape, it is also commonly referred to as an "O-ring." The material can be customized, but oil-resistant rubber materials are primarily made from NBR (Nitrile Butadiene Rubber) or Viton. Additionally, EPDM (Ethylene Propylene Diene Monomer) and CR (Chloroprene Rubber) are often used for their excellent resistance to acids and alkalis, solvents, weathering, aging, and air-tightness.