Chatsworth CPI Sliding Rack Shelf 12339-719 / 12339719 (NEW OPEN BOX). These specially designed shelves are suitable for applications where there is a need to access installed equipment for maintenance, upgrading, cleaning, etc. The pre-assembled cable management arm prevents tangles, twists and damage from cuts, kinks, etc. during shelf extension or retraction as well as maintaining proper bend radius of cable. Shelves mount to the four vertical mounting rails. Depth is 18” to provide clearance for cables, ventilation, power strips, etc. Shelves have adjustable mounting depths of 14” to 24” for the 18” shelf. Vented shelves are designed to optimize air flow. Extends 17”. Made of strong, lightweight aluminum. Shelf locks in closed or fully open position, providing stability. Supports up to 140 lb Ships fully assembled, installs using 8#12-24 screws (not included) Installsfully assembled (screws not included)