– Provides tool-less support for 4-post racks – Support a wider variety of racks The ReadyRails™ static rail kit from Dell™ provides tool-less support for 4-post racks with square or unthreaded round mounting holes including all generations of Dell racks. 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.