Review: Auralex Monitor Isolation Pads (MoPAD)
Positives:Good price, good job of isolation
Negatives:basic auralex foam, look old after a while
These get the job done at over half of the expensive ones. I have had these for a while and do not notice any sympathetic vibrations on my desk. That is after all the only thing they are supposed to do.
They come with wedges that when added make them flat and when removed provide an angle.
If you are on a budget or dont feel like spending a whole lot on something that just sits under your monitors then these will work fine. If you want more serious isolation and better looks auralex makes a pro pad and there are also primacoustic recoil stabilizers both at least twice as much.