For basic ganging rack requirements, Atlas offers the newly designed 540-25. The 540-25 is 22-5/16" wide, 25-1/2" deep, and has 40 vertical panel spaces. The 500 Series Cabinets are welded 16-gauge CRS and assembled for immediate use. Rear doors are hung with quick-release spring hinges which allow them to be rotated 180° for right- or left-hand opening. See chart on back for optional front door model numbers. If front door is ordered, it will be keyed differently than the rear door for security. Cabinet frame and rear door are vented to promote air circulation and heat dissipation. The 500 Series line offers several installer-friendly advantages includ­ing a 6 RU standard panel width opening in the cabinet top and conduit arrays. The top opening can be left open for free wire access/ventilation, partially covered with the ISOPANEL™ for non-conductive cable access or closed using 2 stan­dard 5 1⁄4" (3 RU) panels. Top opening is also perfect for installing EFP Series fan. Multiple conduit arrays provide maximum access, and are conveniently located on the top and bottom panel surface, and across the top and bot­tom back flanges of the cabinet frame. Surface arrays are comprised of 4 knockouts: two 1" (25 mm) standard knockouts and two 1⁄2" (13mm) / 3⁄4" (19mm) concentric. Flange arrays consist of five knockouts: three 1" (25 mm) standard and two 1⁄2" (13mm) / 3⁄4" (19mm) concentric. Cabinet frame and rear door are vented to promote air circulation and heat dissipation. Includes one pair of 12-gauge CRS adjustable mounting rails tapped 10-32 (544-30 includes 2 pair 12-gauge mounting rails) Cabinets have welded top and bottom panels with panel-opening vent; removable rear door with Cabinets feature front-to-rear mounting rail supports with slotted cutouts to easily adjust rail depth and to provide open raceways for vertical cable pathway. (Note: Number of supports per side vary depending upon model selected — 40 RU & 44 RU models = 4 per side; 35 RU model = 3 per side). Cabinet surface is phosphate pre-treated for proper paint adhesion. Standard finish is textured black epoxy #962.