DiversiTech MP2-E E.V.A. Anti-Vibration Pad, 2" x 2" x 7/8" , Pack of 4

I bought these to help with the vibration from my portable air conditioner. The pads work brilliantly and the violent start and stop of the compressor no longer reverberates through the whole role room, only a loud click from the unit itself now.This pad size is too small for castor wheels and kept rolling off. I cured this with cheap castor cups.

The three lower ones are this article - I thought it would be according to the picture and also have the same stability as the one I bought 1-2 years ago, which is the top one (also with a different color). After two months of using them under my bed, the result is as shown in the picture. The effect also vanished within these two months. The quality between the former article and this one has decreased considerably and does _in no way_ justify these costs. It is just not the article as described and advertised. I thought the color change would not make such a significant difference, but appearently it is due to a change in the material rendering it completely useless.

You would likely get better sound isolation from a pair of cheap gymnastic mats, fold them and put your bed or whatever on top. I don't see the purpose of these, they're clearly visible even though they're small so they could just have been bigger.