Abstract: A unitary device for venting a rocket motor of an ordnance item having a warhead comprises a circumferential belt containing a cutting explosive charge and constructed for removable mounting around a housing of the rocket motor, and an activating device having a casing permanently connected to the belt. The activating device further includes, in the casing, a striker for movement therein, a spring located and operatively associated with the striker for urging the striker toward the primer from a rest position, and a latch for retaining the striker in said rest position, said latch including a part of eutectic alloy normally opposing movement of the striker and becoming ineffective above a predetermined melting temperature.