This is the complete “drilling machine” that consists of pumps, a derrick or mast, a substructure, blowout preventors, drill pipe, drill collars, mud tanks, a rotary table or a top drive and three or four engines to power the equipment. This rig only drills on land. The drilling crew consists of one toolpusher (the boss on location), the driller (who operates the machinery), two or three roughnecks (rig workers that do a lot of different tasks), and a derrickman (who goes up in the mast to “rack” drill pipe when it is put into or taken out of the well). This is different from a workover or completion rig in that this machine actual does the drilling. A workover or completion rig is used to “complete” the well, put tubing in the well, and set it up to produce. A completion rig does not drill. Companies that supply these rigs are Helmerich and Payne Inc., Nabors Industries, Patterson-UTI Inc., Unit Corp, and others. Companies that manufacture the components that make up a drilling rig are NationalOilwellVarco, Caterpillar, Tesco, and others.