DESC: These rolling-pin style Pneumatic Drum Sanders are perfect for hand contouring and smoothing projects that are too large to use with a stationary sander. Simply chuck the 3/8" spindle into a portable electric drill, cordless drill or air powered drill for two-handed control. Choose the 4" x 1 1/8" diameter size for getting into tight areas and the 7 1/2" x 2 1/4" diameter size for fairing broader areas. Each features ball bearing handle and air valve for easy bicycle pump inflation.