It is used to keep the API adaptor clean and tidy and to prevent against dust, water and other impurities, protecting the outer surface of the API adaptor interface from being damaged, and prevent oil leakage when the API adaptor is not tightly sealed. The aluminum alloy material is oxidized and has strong corrosion resistance, light weight and durability. The interface standard complies with API RP1004 standard. It can interface with standard API. The valve body is equipped with lead sealing holes and can be applied with lead seals.