Sound Addicted - Studio Monitor Isolation Pads for 5 Inch Monitors, Pair of Two High Density Acoustic Foam which Fits most Speaker Stands | SMPad 5

The material is pretty legitimate

Put these under my budget Edifier R1700BTs speakers and did notice an increase in sonic clarity due to presumably less cabinet vibration. Voices and instruments seem more separated in the mix, perceived increase in resolution (likely just a bit less "muddiness"). No downsides I can hear. I'm sure bass is also improved. Foam is quite dense and seems good quality. Obviously easy to install -- just place under your speakers. I also love the understated look -- no logo or other distractions, just black. An easy recommend for the price/performance improvement.

Em uma semana de uso, com um monitor de áudio Yamaha HS5, a espuma ficou toda deformada. Não recomendo!

These are the ones you want.

Arrived rather quickly despite stating a 3 weeks delivery timeline. Added the foam below my woofer. Hope it does helps in reducing some, if not all the vibration!

Me sorprendió la firmeza que tiene la esponja para no deformarse con el peso de mis monitores. Ayudo a disminuir la vibración del escritorio y la posibilidad de ajustar el angulo de inclinación es perfecta para mis necesidades. Sin duda lo recomiendo.