1)According to the number of ram installed in each set, ram BOP can be divided into: Single ram, double ram and three ram BOP, which are respectively installed with one ram, two rams or three rams. 2) According to the ram opening and closing method, ram BOP can be divided into manual locking and hydraulic locking. 3) According to the different opening and closing method of bonnet, ram BOP can be divided into two forms: Rotating bonnet ram BOP and linear bonnet ram BOP. For the rotating bonnet ram BOP, when opening or closing bonnet, the bonnet rotates on the hinge sear fastened on the body, the ram cam cavity shape of such BOP is rectangle. 4) For the linear bonnet ram BOP, when opening or closing bonnet, the bonnet makes linear motion along the two bonnet opening and closing plunger rods fastened on the body, the ram cavity shape of such BOP is elliptic. Connection types:The BOP are offered with studded, flanged and hubbed top and bottom connections. The sizes of flanges, bolts, clamps and ring grooves all conform to API 16A and GOST standards.