Mast is triangular, tubular, welded. At the top of the mast there is a quadruple crown block, where two rollers are intended for feed unit. Rollers diameter is 360 mm. The mast is pivotally fixed to the rack. In the operating position the mast legs are fastened by locks in the main rig frame.
Front legs have jacks that relieve the rear axle of the vehicle. The mast has swivel guides. The top of guides are bent. It permits to move aside swivel together with the kelly bar during round-trip or to set the rig in transfer position.
In the transfer position the mast is laid upon the front foot and secured by the automatic fastener; the kelly bar is laid on the front mast girth and fastened to the bottom girth.
Welded joints of the mast should be periodically checked.