It is a sander, usually air driven, like 52Ton says. It rotates while revolving in an ellipse.(Dual Action) Uses all grits of paper. Takes off paint without grooving and just floats across the surface nicely. Does not do curves unless you are well experienced. Will do large curves and flat very nicely. Does take off paint fairly rapidly. Lots of paper, lots of dust. Just run a fan while working, blows it away from you. You need a mask also.
