Work Well for Vibration Isolation on Audio Equipment
I placed three of Iso-Puck 76 under my SACD Transport. They really work well in vibration isolation. These are rated 80 pounds each.so you can put heavy speakers, subwoofer or equipment on top. In my case I found they work well with my digital source component. But they do not work great with preamp because my preamp is lighter so this is an overkill.
But I recommend them for purpose stated above.