Holmatro hydraulic mast jacks are used to pre-tension the rig. Holmatro’s through-bar mast jacks are available in aluminium or painted steel. The popular aluminium jacks are supplied as a complete set with a hand pump, hydraulic hose, plug-in pressure gauge and carrying case. The stainless steel in-mast jacks are mounted upside down in the mast on a permanent basis. A complete set includes a tilting saddle, a hand pump with mounted pressure gauge, a hydraulic hose and quick couplers.