This socket is ideal for installing M12 nuts and bolts into a channel It's design enables the socket to slide through standard 41mm x 21mm unistrut It allows you to fit standard channel/unistrut to a wall ceiling or floor without the need to use brackets 1/2" square drives so you are able to use a ratchet or torque wrench for fast and accurate installation Six-sided socket diameter: 19mm Overall Length: 70mm