Variable bore packer for a ram-type blowout preventer

Variable bore ram

Variable choke for use in a subterranean well and method of...

Variable choke valve

Variable controlled guide device for wireline spooler

Variable depth grooved drill string member

Variable diameter earth boring bit

Variable discharge surge feeder and bolter

Variable downhole choke

Variable flow resistance system for use in a subterranean well

Variable flow resistance system with circulation inducing...

Variable force/variable frequency sonic drill head

Variable gauge drilling apparatus and method of assembly...

Variable gauge stabilizer for directional drilling

Variable geometry cluster drill

Variable hydraulic resistor jarring tool

Variable length/capacity elevator links

Variable linkage assisted gripper

Variable orifice casing filling apparatus

Variable orifice gas lift valve assembly for high flow rates...