An electrical plug-in connector/an electrical connection system is used between a socket of an igniter module and an electronic control unit for a restraint system in motor vehicles. The plug-in connector comprises a housing with one or more locking arms for locking the housing to the socket. The locking arms reinforce the lock mechanism when a force is applied to pull the plug-in connector from the socket without actuating the locking arms. Alternatively, the plug-in connector/connection system comprises a housing with one or more locking arms that are selectable between a locking position and an unlocking position. The locking arms are at least partially elastic, and serve to lock the housing to the socket. When a force is applied to pull the plug-in connector from the socket, the locking arms are locking when in the locking position and releasably snapping when in the unlocking position.