A. The fixed rack is 12" long overall and surface mounts to the underside of an existing shelf using the included screws. Rail spacing is 1", with a 3-3/16" mouth and a 2-1/8" drop.
B. The 14" holder rods can be spaced variably and are bolted through an existing shelf. The rod drop is 2-3/4" and the mouth will be about 2-1/2" wider than the rod spacing you use.