The ReadyRails static rail kit for 2U Systems, including PowerEdge R720 provides tool-less support for 4-post racks with square or unthreaded round mounting holes including all generations of Dell racks. It also supports tooled mounting in 4-post threaded racks and 2-post (Telco) racks for added versatility. The static rails support a wider variety of racks than the sliding rails but do not support serviceability in the rack and are thus not compatible with the CMA.