Because pneumatic sanding drums conform to shapes, they do a better job on compound curves than regular hard-rubber drums, which will flatten high points. You can vary their hardness to suit the job – a soft drum is best for convex surfaces, and a harder drum is good for inside curves and flat surfaces. Easily inflated (to 15 psi or less) with a bicycle pump.
The medium drum has a 5/16" shank and measures 2 1/2" in diameter by 3 1/2" long. The large drum (3/8" shank) is 3 1/4" in diameter by 5 1/4" long. The carver's drum measures 1 1/2" in diameter by 4" long, with a 5/16" shank.
All can be used in a drill press, on a chucked motor arbor, or on a lathe with a headstock chuck. The medium drum can also be used in an electric hand drill. The carver's drum is best used in an electric hand drill or with a flex shaft.
The drums and sleeves are available separately or sold in sets that include the drum and three sleeves (one of each grit). Replacement cloth-backed sleeves are available.