Eia310d Standard Pdf -

Exactly 18.312 inches (465.1 mm) . This is the horizontal distance between the centers of the mounting holes on the left and right vertical rails.

: A repeating pattern of three holes within one rack unit. The holes are spaced at 0.625", 0.625", and 0.5" on center (from bottom to top). eia310d standard pdf

Standard in modern enterprise data centers and server cabinets. Exactly 18