Product review (5 stars): Excellent investment!
Our Whirlpool Duet washer was stuck in an irritating pattern- fine for a while, then suddenly it would walk across the concrete basement floor and inevitably leak.  I would check and sure enough, the feet were loose and it was out of level.  I'd level it back up and tighten the feet back, only to start over in another few weeks.  I was wishing I had my old top loader back.  My wife was fed up and giving me grief about getting someone in to fix it "because it must be broken".  Before I gave up and called for service, I was directed to these by an online appliance newsletter and I figured, why not?  I was skeptical, but figured I would give them a shot.  Cheaper than a service call, anyway.
Two months later, the washer has not moved an inch. No more loose feet, no more leaks, no more irritated wife. I only wish I had known about these sooner!