Dental Hand Grinder 90 Micromotor Polishing Handpiece with 102 Handle 35000 RPMDental Hand Grinder 90 Micromotor Polishing Handpiece with 102 Handle 35000 RPM. The polishing micromotor fits all type of dental laboratory works and some other situations, such as Denture Jade Nail Stone Wood Polishing and Carving Instructions When in use, the handle must be securely engaged before starting, otherwise the motor may overheat due to idle transfer!!! The handle cannot be filled with oil or water, otherwise the bearing is prone to