The UM convertible-bonnet ram-type BOP is a lightweight BOP designed for easy maintenance and long life. It complements our U BOP and includes bonnets that can be installed on any comparably sized U BOP. Its design incorporates a single bonnet that can be converted between shear and pipe modes, eliminating the need for a separate shearing bonnet.

Optional bonnet seal carriers eliminate high makeup torque on bonnet studs. The UM BOP allows seal replacement with the bonnet in ram-change position without having to remove the bonnet. Wedge lock operating systems are interlocked using sequence caps to ensure that the lock is retracted before applying pressure to open the BOP.


  • Application: Offshore (surface) and onshore
  • Bore Sizes and Working Pressures: 7 1/16 in, 11 in, and 13 5/8 in rated 3,000 to 15,000 psi; 16 3/4 in rated 3,000 to 10,000 psi; 20 3/4 in rated 3,000 psi; 21 1/4 in rated 2,000, 5,000, and 10,000 psi; 26 3/4 in rated 3,000 psi
  • Body Styles: Single, double, triple, quad
  • Pressure-Energized Rams: Yes
  • Lock Type(s): Manual locks standard; Hydraulic locks optional
  • Hydraulically Opening Bonnets: Yes
  • Bonnet Studs Instead of Bolts: Yes
  • Available Bonnets: Large-bore bonnets and FXT bonnets available for increased shearing and sealing capabilities
  • Field-Replaceable Items: Bonnet cylinders, pistons, seals
  • Manufactured in accordance with NACE standards and capable of being monogrammed to API 16A