TE Connectivity M Series Guide Pins and Sockets M Series guide pins and sockets made from stainless steel. These guide pins and sockets are used for aligning connector halves during mating. Centre guide pins and sockets are used in housings that have a single mounting hole as well as in the centre hole of housings that have 3 or 4 mounting holes. Corner guide pins and sockets are for use in corner holes of housings that have 2 to 4 mounting holes but cannot be used in centre mounting holes.