SKB's line up of Shockmount cases is un-surpassed in the industry. The original workhorse 20" deep cases have served industry for over 25 years and now include Telescoping handle & wheel cases. Military quality cases are available with a patented " Swing Door " so the lid doesn't have to be removed to use the content. The 24", 28", 30" cases include heavy duty casters. The 28" case has Dell type square holed rails and the depth is made to hold the longer Dell servers.