Service module for hostile environment

Single acting hydraulic fishing jar

Sleeve valve hydraulic jar tool

Soil displacement hammer with movable head

Spline drive for percussion drilling tool

System and method for installing production casings

System and method for installing production casings

Telescoping torque transmission apparatus

Temperature compensated sleeve valve hydraulic jar tool

Temperature compensating hydraulic jarring tool

Tension shock absorber device

Thread joint

Transmission sleeve

Transmission sleeve for a down hole hammer

Transmission sleeve for a down hole hammer

Tubular spring slip-joint and jar

Two way hydraulic drilling jar

Underground piercing tool

Unitary drill bit and roof bolt

Valve assembly for a downhole to remove bore hole subsidence