Abstract: A release comprises cylindrical first and second connectors having supply passages, one of which is mounted on the supply tube and the other of which is mounted on the mask. The first connector has a cylindrical chamber for receiving a cylindrical portion of the second connector to connect the connectors and operatively connect the tube to the mask to enable supply of breathing gas to the mask. The second connector has a groove formed in its outer surface for receiving a split spring ring carried by the first connector. The free ends of the arms of the split ring have cam surfaces. A spring is mounted on the second connector and is compressed by insertion of the second connector. An unlocking device comprises an electrically-actuated explosive device carried within the first connector and a wedge which is projected against the cam surfaces upon actuation to force the spring arms apart, to force the split ring out of the groove.