Main nut and safety nut made of bronze (no plastic) with high resistance to wear, for greater safety. Steel high resistance rolled screws, to provide long life. Automatic and permanent nut lubrication system. Tubular structure made of 5 robot welded sections, nothing sturdier in the world. Shaft drive + Space Saver Small base, allows easy access into the working area. Self Supporting Base + Shaft Drive The exclusive RAV lift with self supporting base and transmission by shaft.