Product review (4 stars): Good quality. May not work for everyone.
I installed marble tile in the room with the washer and dryer and thought these would be a good way to protect the floor as well as absorb some noise and vibrations.  It does protect the floor.  But they allow the washer to rock a lot more. The washer really rocks a lot more than it used to. That causes pretty severe shaking and if the washer is just far enough from the dryer to touch it it sounds like the washer is going to bust through the wall.

I'm now looking for some hard rubber pads that I can double stick down to the floor and I'll get rid of these pads.