A piston (reciprocating) compressor uses pistons controlled by a crankshaft to deliver the gas at high pressure. These are typically found at smaller worksites and aren’t designed for continuous use. Two stage compressors have two compression chambers on either side of a piston. Double-acting compressors are typically water-cooled by a continuous stream of water through the engine. This provides a better cooling system than other compressors. Due to their high cost, two stage compressors are better for factories and workshops versus private projects. .