CALIBER MULTI GLIDES. Extension kit for 12 trailer. Black only - standard width. Kit includes four 2-1/2 glide sections. Kit is as an extension for the multi-glide double set to accommodate 12 trailers. The four 2-1/2 sections are to be added to the front of the trailer. Can only be with Multi-Glides. For more information on this product check out this video.