The PWB-323XL-ESK kit includes the 3” extra large back box that has up to 2” KO’s and include flush cable-tie mounts, 4 triple play mounting solution openings for AC/AV/IT applications and three optional adjustable locking shelves for mounting equipment. Also an internal shelving system that has two adjustable shelves include a hole pattern that allows for any screw spacing from 3/8” to 11¾” including multiple VESA 100 hole pattern locations.