Product review (5 stars): We installed these under both the washer and dryer on ...
We installed these under both the washer and dryer on our new front-load pair.  By having the installer do it at time of delivery, it saved a lot of heavy lifting. Although probably only the washer needed them, using them under the dryer kept them both the same height, and quieted the dryer compared to the one it replaced.  We never operated the washer or dryer without these, so I can't make a comparison without them, but with them, both are more quiet than the top-load Maytag pair they replaced.