The RX21-25SFD mobile cabinet is ruggedly constructed of 16-ga. CRS and include heavy-duty casters. Equipped with a front pair of 11-gauge CRS adjustable mounting rails tapped 10–32 on standard E.I.A. 5/8"- 5/8"-1/2" spacing. Optional RR21 rear mounting rails are available for additional support. Front-to-rear mounting rail supports have slotted cutouts to easily adjust rail depth and to provide open raceways for containing vertically run wire and cable.