The new model PLW 923 S Air Stone Sander/Polisher from Flex North America is a compact, lightweight polisher that allows for all-day operation on granite, marble and concrete. Features include a central water feed with rear exhaust and a maximum speed of 3,600 rpm. The tool weighs 2.8 lbs., it accepts 3-, 4- or 5-in. discs, 90 psi air pressure, and a 1/4-in. air inlet/hose size.