(1) Heavy rubber seals in a [[blowout preventer]] which can be closed to provide pressure control. One of three types – blind, pipe, or shear – may be installed in several preventers mounted in a stack on top of the wellbore.

a) Blind rams, when closed, form a seal on a hole which has no part of equipment extending through the blowout preventer.\\
b) Pipe rams, when closed, seal around any pipe standing in the hole.\\
c) Shear rams, cut through drill pipe and then form a seal.

(2) Well-logging companies furnish blowout preventers with modified rams which can be closed down over [[logging cable]] to provide pressure control. Will not damage cable.