Skid Unit is the term used to describe the Bare unit that is a stripped down tractor often sold by manufactures to companies the build specialist machines OEMs. The Unit consists of an engine, Gearbox and rear axle unit, which many have wheels fitted in some cases, but often not. Usually supplied fitted to a Timber Pallet or Skid to keep it off the floor and enable easy handling in transit. There may be auxiliary items fitted, like front axles, steering box, controls, rear linkage, hydraulic pump etc. dependant on specification required from by the customer.