A needle scaler, also called a needle gun scaler or needle gun, is a small, handheld tool that uses pressurized air to force long chisel needles back and forth. The needles move rapidly across a surface to remove debris, rust, scale, and old paint from metal workpieces. Mechanics, metal workers, ship workers and many others find the needle scaler indispensable. While most models are operated by compressed air, newer electric models are available.