The formal DEC name is "prefilter" (since the air that comes in here goes through the cards, and the air blower, and then through the absolute filter on the way to the pack), and the metal thing that holds it on is the "frame". Here you go: http://gunkies.org/wiki/RK05_disk_drive#Prefilter_frame pictures and all the dimensions I could think of to measure. (I didn't bother with the hole locations, since you can get them off the drive.) The little hand-knob-bolts are DEC standard (used elsewhere too). Noel