dual/4/8 polishing head can be choosed,fast operation and higt work efficiency,provide technical support and video tutorials,white polishing machine with air compressor,black polishing machine need to additional configuration,lcd scratches refurbish artifact the grinding & polishing machine is used to refurbish the phone screen, back glass and apple watch screen. refurbishing the screen and back glass is a necessary step for refurbishing factories and pre-owned phone recycling companies. the old way to refurbish the screen and back glass is to replace the front glass and back glass,which is not only difficult and costly but also less efficient,.syi