30" 3SKB Roto Shock Racks feature a depth of 30" from front to rear rail to accommodate deeper servers, with lid depths of 4.5" per lid. All 3SKB Series Roto Shock Racks feature a compound hinge system that allows the lid to swing out and completely around to lie flat against the main body of the case. This also enables effortless removal/reinstallation of the lid with a simple lift motion. Both front and rear lids are designed to protrude into the base of the case approximately 1" with a unique double wall structure that makes them incredibly rigid where this intersection occurs, providing MIL-SPEC sealing characteristics with significantly fewer latches than most competitive cases. This revolutionary design allows for rapid deployment in an up-right configuration, even when stacked -- 3SKB Roto Shock Racks are the only shock racks in the marketplace today that will open front and back while stacked. The inner rack chassis is built of high strength / lightweight aluminum alloy and 11 gauge hot rolled carbon steel rack rails to EIA-310 standards, creating an H-shaped frame that provides maximum strength. Shock and vibration mitigation is accomplished with eight (8) elastomeric isolators rated for a payload range of 40 - 150 pounds in a standard configuration, and up to 300 pounds in a special order extended payload configuration allowing adequate sway space for ambient air circulation and heat dissipation. The rack rails come pre threaded for standard 10-32 hardware and mounting screws are included. Other standard features include an automatic ambient pressure relief valve and removable 4" casters.