Х-ка 4:
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.
Х-ка 3:
It also supports tooled mounting in 2/4-post threaded racks and 2-post (Telco) racks for added versatility.
Х-ка 2:
The ReadyRails static rail kit for 1U Systems provides tool-less support for 2/4-post racks with square or unthreaded round mounting holes including all generations of Dell racks