The background: during the spin cycle I was regularly in front of the washing machine, armed with a wrench to time in or out turn one or the other foot in the resulting vibrations. The course helped only for the moment.
It was also important that the machine was aligned with a spirit level or not: the wooden floor just does not impose enough contrast.
Now, the vibration was with great expectation placed under the washing machine (do you do better in pairs).
The recesses for the feet of the washing machine are sufficiently large so that the feet are not overly must give a lot of trouble when aiming.
Now quite a few wash loads were cleaned, my Conclusion: Highly recommended !!
The vibrations of the machine are very effective intercepted. In addition, the machine is very non-slip.