From the Manufacturer
Welded one piece mobile base, features the HTC exclusive 3-point system which provides a solid, stable stance and no need to relevel after moving. Two rigid wheels with locks and one locking swivel wheel make moving your machine in any direction a breeze. And, your machine is held 3/4″ off the floor at all times, eliminating the need to recalibrate those important machine setting that can be thrown off by raising and lowering the machine
“Easy Machine Movement, Guaranteed – Htc Mobile Bases Work Better Than Any Caster System ”