Specification of Blowout Preventer(BOP):
1, Blowout Preventer(BOP) can seal any size of annular space with a kind of rubber if there is a drilling tool, tubing or casing in hole.
2, When there is no drilling tool in hole, it can seal the well head completely.
3, When the well blowout and overflow happens during drilling, coring or well logging, it can seal the annular spaces between Kelly, coring tools,  cable, wire line and well bore.
4, Under the control of the hydraulic control system which is equipped with a depressuring pressure regulating valve or a cushion accumulator, Blowout Preventer(BOP) can force stripping with 18° tool joint.  

Available
Working Pressures (PSI)	Bore Sizes
	7-1/16" (180mm)	11" (280mm)	13-5/8" (346mm)	16-3/4" (426mm)	18-3/4" (476mm)	20-3/4" (527mm)	21-1/4" (540mm)	26-3/4" (680mm)
15,000	√	√	√
1,000	√	√	√	√	√		√
5,000	√	√	√	√			√
3,000	√	√	√			√		√
2,000							√	√