Two female square adaptors to take ratchets, sliding T bars, extensions etc. A strong magnet securely holds the socket rail to ferrous metals Additional holes are provided for wall mounting the socket rail or attaching to non-ferrous materials The sockets are securely locked by the ball at the square-drive end by turning them 90 It is a simple matter to unlock and remove the sockets, by turning them 90 in the opposing direction Delivery without tools Delivery without tools