7 '' / 9 '', star Speed, mighty, 12. 0a, all ball bearing construction for yearn life, natural philosophy master maintains such as Speed under load delivering craved finish results, conveniently situated star Speed dial lets user set boundary Speed from 0-600/3500 RPM for dissimilar materials & applications, star Speed trigger allows user to master Speed from 0 to dialed boundary setting, heat treated, precision cut steel gears for free operation, feature brush caps for tardily servicing, boastfully spindle build button allows for tardily & promptly backing plate changes, 2 position select handle & rubber backing pad.