O.D. = Outside Dimension
Because of the unique design of the Rack cast zinc alloy corner (see shadowed corners in graphic images above), 1 vertical rack unit of space, at both the top and bottom (see image at left above), is used to form the Rack height. However, the unique design adds 3-3/4" to the U height & 2-3/8" to the width and depth dimensions when measuring rail-to-rail (see images above). To determine the outermost dimension of your Rack, be sure to add 1/4" to account for outer wall thickness of the cast metal corner.