Product review (2 stars): Makes a 20% difference...
My washer walked so badly it practically ran. I was desperate for a product that could help. I had to actually call out a repair technician as my center post washer was out of balance.

I have tile floors, and even after the balance issue was taken care of the walking would still happen.

When I got these feet (which are ideal for tile floors) there bottom side has a more flexible "grippy" rubber. I scrubbed the floor clean so there was no dryer lint, or dust elephants - I was guessing that a clean floor would help the grip and thus help stop the walking.

After my husband and I lifted the washer and put the 4 feet in place (not an overly fun job), we ran a load of wash. While the machine did quiet down some - it also did still walk (even with the feet!) The feet are also relatively tall so the washer and dryer were no longer close to the same height and I couldn't iron on top of the double units.

They worked (kind-of) for the few weeks it took for the technician to get proper specific rubber feet for my washer. If your unit is only walking a little this may be just what you need!