The milwaukee m18 frop21 fuel 18v cordless brushless random orbit polisher features a 21mm stroke that allows for fast and efficient polishing, while the variable speed control allows you to easily adjust the speed to match the task at hand. The polisher also has a convenient lock-on switch that lets you work continuously without having to hold down a trigger. Features & benefits 21mm orbital function for fast and efficient polishing with a free hologram finish 8 position speed dial selection for maximum control and best finishing results 90 rotated battery slot with a clearance of more than 50mm delivering equal performance as corded random orbital polishers to complete polishing and heavy-corrections large ergonomic front grip area with overmold for easy and comfortable handling line-lock-out function to prevent automatic start up lock-on function provides more comfortable and less strenuous use when polishing milwaukee's powerstate brushless motor and redlink plus electronic intelligence delivering outstanding power, run time and durability removable dust screen to prevent debris entrance, prolonging motor life specifications battery type: milwaukee m18 lithium-ion battery voltage: 18v backing pad diameter: 150mm diameter of orbit: 21mm no load speed: 2,400-4,500rpm sound power level uncertainty: 3db a sound power level: 88db a sound pressure level uncertainty: 3db a sound pressure level: 77db a stroke length: 21mm vibration polishing uncertainty: 1.5M s vibration poli...