Abstract: In a mechanism designed to release a stored gas from a storage bottle. A reciprocating valve plug is held in a retracted position by a cocking arm which is in turn held in position by a lock lever which is in a lock position. A firing lanyard has an end portion connected to the lock lever such that when the firing lanyard is pulled the lock lever pivots out of contact with the cocking arm. The lock lever is urged into its lock position by a torsion spring. Once the lock lever is moved to its release position, the cocking arm is immediately urged to its release position by a torsion spring acting thereon. The cocking arm torsion spring is stronger than the lock lever torsion spring thereby enabling the cocking arm to hold itself and the lock lever in their respective release positions.