1. Main parts made of tungsten and alloy steel, with heat treatment and fine ground finished. 2. HB type speed 230 rpm per minute. 3. HBH type speed adjustable, from 230 to 400 rpm per minute. 4. HBH type without copper or bevel gear, equipped with bearings. 5. HBH type use electro magnetic type brakes and clutches. 6. HBH type use proximity sensor for positioning.