This polypropylene rack accommodates a cover-glass in all sizes by simply adjusting the holder to fit the cover glass and then securing it by tightening the reset screws with the hex key. The holder is made from non ferrous material, so it is microwaveable. The rack accommodates 10 cover glasses, round, square or rectangular, adjusting from 5 mm to 60 mm. Removable handle. Rack comes with two set of holding rods. One set accommodate cover glasses from 5 to 25 mm, and the other set for cover glasses from 5 mm to 60 mm. Rack measures 1-1/2" W x 1-1/2" H (48 x48 mm).