The Ready Rails static rail kit for 2U Systems, including Power Edge 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 & 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 & are thus not compatible with the CMA. Designed For Power Edge R510, R515, R520, R530, R720, R720xd, R730, R730xd, T430; Power Vault DL2000, DL2200, NX3100