ProX X-6UE Rack CaseNotes 4U + 2 space rack drawer for total of 6U It is 12" from the rack rail to the back padding. There are only rack rails on one side. A ProX X 6UE Rack Case in Excellent condition! At Evolution Music, we attempt to highlight cosmetic defects (if any) by picturing every angle of every piece of gear so you know exactly what you are getting. We always picture any and all accessories too. What you see is what you will get so please check out the