For basic ganging rack requirements, Atlas offers the 544-25. The 544-25 is 22 5/ 16" wide, 25 1/ 2" deep, and has 44 vertical panel spaces. The 500 Series Cabinets are welded16 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 includÃ‚Âing 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 ISOPANELâ„¢ for non-conductive cable access or closed using 2 stanÃ‚Âdard 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 botÃ‚Âtom 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.