... take darkjuggalo's advice - you have the advantage of having the board 'in hand'; look around for the price range you're looking for, then start comparing size. NewEgg is a good place to go (assuming they carry all your 'candidates'), as they usually have a 'manufacturer's link', as well as a batch of photos posted; use the mfg's site to d/l a manual and dimensions; use the photos to judge 'where the mount is', relative to the body of the exchanger (most, but certainly not all, will be centered); if they can't be bothered to post dimensions for their products - you can't be bothered to send 'em a check for their product!