Our 3 Inch Slide Tracks come in 8 inch segments.  If you wish to join more of them together to make longer runs of track, E.g. 2x8" = 16 inches of track run, you will need one of these for every 2 tracks you want to join together; so 2 for 3 tracks and 3 for 4 tracks and so on.  Machined from aluminum and hard anodized with stainless steel fastener pack.