The P604 lockout device secures the male piece of differently sized compressed air couplings against unauthorised use. Compressed air can also pose considerable danger, so pneumatic connections should be secured against unintentional use. The P604 pneumatic lockout device takes care of this simply and reliably. With its seven different diameters for accommodating the male parts of a wide variety of couplings, P604 offers the scope to be able to secure almost all common compressed air connections.