This type of oil rig is commonly called by several names such as completion rig, workover rig, or pulling unit. The terms are interchangeable and mean that the rig is usually only capable of pulling pipe (tubing) in and out of the well. It consists of a large truck with a drawworks (large winch) and a telescoping mast built onto the bed and chassis. The truck is backed up to a well that has already been drilled, the mast is raised and extended, and the work begins. This rig only requires three men to operate and only works during the daytime. These rigs cannot drill unless equipped with a special equipment package called a “power swivel.” This type of rig is used to “complete,” repair, or swab existing wells. It is a general service type of equipment that can do many things, but is primary used to remove tubing from a well or place tubing in the well. Companies that supply this type of equipment are Key Energy Services, Pool Workover Services, and Basic Well Services.