The 4V Battery Powered 5-Speed Rotary Tool is the best cordless rotary tool on the market. This rotary grinder has a keyless chuck design . with a variety of speeds to choose from so you can match power to your specific task. The dedicated on/off switch provides increased user control and the enhanced portability offers extra convenience. The increased comfort grip will help you work for hours without tiring your hands out . while the tool free bit change makes it easier than ever to get back to grinding! We’re not sure how you ever lived without a battery powered rotary tool . but now is the time to make the switch. If you call yourself a hobbyist . do it with HART.