hang on back

See my last question for the background. I'm debating whether to take out back panel anyway. But can a hob filter hang on .5 cm of just glass? I really want this one: Preferred hob updated!

Cascade 80 HOB Filter Summary   The Cascade 80 is a small HOB (Hang On Back) filter for 5-10 gallon aquariums. It is powered by a half inch diameter impeller and makes very little noise other than the sound of water falling over the edge of the waterfall outlet. The intake tube is telescoping...