Pneumatic Quick-Disconnect Lockouts isolate pneumatic energy without the expense and inconvenience of installing in-line lockout valves. Device is applied to the male fitting, isolating equipment from all compressed air sources. Accommodates the majority of 1/4 in., 3/8 in. and 1/2 in. male fittings. Hole in center of device allows for permanent storage on an air hose and a loop on the side can be used to hang the hose and lockout device. Accepts padlock with up to 1/4 in. shackle.