Abstract: A lockout device (10) for a male hose fitting (54) has a body (14) with a bore (22) extending therethrough. A moveable sleeve member (32) is mounted on the body. A plurality of holding balls (30) extend into the bore. In a first position of the sleeve, the balls fully extend into the bore, and in a second position of the sleeve the balls are enabled to move radially outward. A hole (50) in the body enables a loop (52) of a conventional lock (12) to extend through the body. When the lock is installed the sleeve is held in the first position. With the lock removed the sleeve may be moved to the second position and the male hose fitting inserted into the bore. Once the hose fitting is inserted, the sleeve member is returned to the first position and the lock extended through the body. The male hose fitting cannot be removed from the device or connected to a source of compressed air as long as the lock remains installed on the lockout device.