Annual BOP must be used with hydraulic control system. It is usually used with ram type BOP,and also, can be used separately.It can be used to seal a variety of shapes and sizes of the drill pipe,drill pipe sub,drill collar,casing etc. It can be used for following operations: 1. It can seal on almost any shape or size-kellys, drill pipe, tool joints, drill collars, casing or wire line. When there is no drilling tool in preventer, it can completely shut off the hole. 2. With an accumulator, forced tripping with 18° welded tool joints is allowed. 3. It is usually with kill/chock manifold, to realize balance pressure drill and is safeties with requirement of much works. Structure Features Spherical blowout preventers consists of just of just five major parts- the upper and lower housing, the sealing element, an adapter ring and a piston. This simple design provides a rugged, reliable preventer and easy of service in the field. Design, manufacture and test standard? API Spec 16A (3th) (16A-0100): specification for drill-through equipment API spec 6A (20th) (6A-0474): Specification for wellhead & X-tree Equipment NACE MR0175-2003/ISO 15156: Petroleum and natural gas materials in H2S environments.