According to the needs of market research, a seating nipple with RN type sealing surface of 2.75 "in accordance with API Spec 14L and" check valve "with rb-2 type and sealing surface of 2.75" are designed.
According to the demand of market research, a "Check Valve" with RN type sealing surface of 2.75 "and RB-2 type and sealing surface of 2.75" is designed, which conforms to API Spec 14L.