This 3U rack tray was good quality, but wouldn't fit our rack without drilling extra holes in the rack ears. The full spec for rack rails includes 3 mounting holes in each rack unit, but many racks only use the top & bottom holes & make no provision for the center hole in each rack unit. The holes in these rack ears were in the center of the top & bottom rack units, which didn't exist in our rack (it's clearer in the picture than this write-up!