AudioQuest Sorbothane Zelfklevende Plaat 6 x 6 x 0.10-Inch

The adhesive backing holds way better than I expected, and trimming it to fit around the top plate vents was easy with scissors. My amp's chassis buzz quieted down noticeably once I pressed a few squares into place.

Stuck a strip of this under my DAC and the transformer hum I'd been chasing for weeks dropped noticeably. The adhesive backing is genuinely tacky, so it grabbed the metal on first contact without me having to clamp it while it set.

Cut a few squares to line the top plate of my amp and the buzzing I'd been chasing for weeks is basically gone. The 0.10-inch thickness is thin enough that it doesn't throw off the fit of the case, and the tacky surface holds without sliding.