Abstract: An apparatus suitable for locking two electrical connectors together is provided, the apparatus comprising: a first assembly comprising a locking member having a radially extending element; a collar with a through hole for receiving the locking member; and a spring positioned between the locking member and the collar, and a second assembly comprising a retaining member having a guide channel such that in use the radially extending element of the locking member is adapted to cooperate with the guide channel to form a bayonet type connection and lock the first assembly and second assembly together.