BOLU manufactures Full Open Valves & Seats and 3 / 4 Web Valves & Seats. BOLU also supplies valve inserts and valve springs, etc. All our valve products are exchangeable with OEM products and meet or exceed API-7K standards. 3 / 4 Web Valves & Seats High strength alloy steel with deep carburized wear surface Stem guided valve with 3 / 4 web seat Excellent performance in extreme environment Exchangeable with OEM products Meet or exceed API-7K standards For more details, please feel free to tell us. Established in 1998, Botou Bolu Petroleum Machinery Factory is a professional manufacturer & supplier of mud pupms & parts. Bolu Petroleum can offer a full lin e of mud pupms & parts together with casing heads, drilling pipe join tools, TDB hydraulic profile control water plugging pump & parts , X-trees and many other oilfield drilling tools. Bolu Petroleum has been granted the API certification. Products are exported to America ,Middle East, etc. Bolu Petroleum is looking forward to being partners with you around the world.