NH-900, Automatic Lens Polisher allow you to safely polish CR-39,glass lenses, high-Index lenses. It is very simply to use because of fully automatic operation. What you need to do is place the lens, set the timer you want and then watch it go. There are 5 different timer setting according to different materials. It's powerful direct drive design eliminates broken or slipping drive belts. Transparent plastic hood is used for inspection of polishing and effectively reduce noise and dust. The accessories include three different polish pads, an accessory exhaust and a polishing stick.