ProCases ACSH20U Shock Mount Rack Case are made of 3/8" plywood A.T.A. construction with all recessed hardware. There is 1" hard foam between inner shell and outer shell. They have front and back rails 20" deep body. They include 3.5" casters on a 1/2" plywood caster board for 10U sizes and above. Casters can be installed on smaller size rack for an additional cost.