Product review (3 stars): It will probably work, if you're careful and buy loctite.
DO NOT USE THE CHEAP FOAM-TAPE IT COMES WITH!!!

I'll make this review quick. Here's what you need to know:
-You have a granite / quartz countertop, and you don't have anything to sink those screws into.
-These are cheap, and they'll probably work, so you buy them.
-You know the tape on the back is garbage, so you buy https://www.amazon.com/gp/product/B000DZD0HC/ref=oh_aui_detailpage_o00_s01?ie=UTF8&psc=1 this 2part Loctite Epoxy from Amazon.
-Peel that crap off the back (it really isn't hard), and clean it w/ Acetone / fingernail polish remover.
-Dry fit everything, totally flush, exactly perfect.
-Mark where these granite grabbers go.
-Pull the dw out, TAPE THE BACKSIDE OF THE HOLE on the granite grabbers (u can't put a screw in if it's full of epoxy).
-Don't overkill the epoxy, this stuff is really strong. Then clamp these in place for 20-30 min.
-Install the dw -- DO NOT CROSSTHREAD THOSE CHEAP, CRAPPY SCREWS -- I did it with one, and it almost made this impossible.