All H&H equipment mounting rails conform to the EIA 310-E Standard specifications for Rack Units & are stamped with Rack Unit numbering & Indexing, and are available as “L”, “U”, “Z”, or dual-plane combination style. Rack Unit hole patterns are either pre-tapped, Universal Square hole or Round through hole. Tap configurations of 10/32, 12/24 or M6, and a variety of Cage or Clip nut sizes are available. Vertical mount U-channel, in broad range of lengths, is also available. WECO or special hole spacing may be optional special request.