It needs 3'' between two cabinets. It cannot go between an appliance and cabinet, or between an angled corner cabinet and adjacent cabinet.

Thanks so much for your help. I have a 39" tall cabinet and a 24" tall cabinet above the microwave next to it, I was going to put it between the two. Could you please tell me why it won't work between them?

cpaolin:

It will work just fine, it's just that you'll be staring at one side of your spices:

Here is a link that might be useful: Rev

It needs a 3/4" panel to cover the side.

Ok, my microwave is 17" tall and will be mounted under the 24" tall cabinet so together they add up to 41" and the filler piece I was looking into is 3" x 39" so I shouldn't be able to see any of the rack. Does the rack only mount to the side of one cabinet? Will it fit if I leave exactly 3" of space? I really want to re hang my microwave but I need to make sure I leave the correct spacing for the filler to fit because once the microwave is hung I can't move the cabinets anymore.

"Does the rack only mount to the side of one cabinet?"

It is designed to mount between panels or cabinet/panel. Can you mount it on one side only? Sure. Is it right? No.

"Will it fit if I leave exactly 3" of space?"

Yes.

Will the people who buy your home smack themselves in the forehead and go "What the heck were they thinking?" Yes.

Haha ok so I won't mount it there. I can slide a cabinet down and mount it between two full height cabinets like your supposed to I just thought it would be more convenient to have a pullout spice cabinet next to the stove where you typically use most of the spices in said cabinet. Or maybe I'll scrap the whole idea and install a 24" cabinet instead of the 21" cabinet that is there now. Regardless I appreciate everyones help and input I can at least install my new microwave in the correct spot knowing 3" is sufficient for the filler.