The rubber core of the blowout preventer is a rubber part that plays a sealing role in the oil well blowout preventer. There are three types of opening plate, rotary type and multi-function type. It is used to prevent blowout during oil development and geological drilling. Its function is to hold various specifications of drill pipes and downhole tools through the control system, seal the wellhead and prevent oil and gas from spraying out. It is generally made of NBR or HNBR and produced by molding.