As well, Iso-Puck's can also be used as an accessory for DJ Gear - Place them under turntables and mixers to isolate them from the supporting surface and reduce the issues associated with vibration and heat.
I run a Sunfire True Subwoofer Signature, a sub with opposing 11 inch drivers with 2 and a half inches of throw each. In short, it moves a lot of air and can transmit a lot of vibration. Recently I had to put the sub in a room with wooden floorboards, not great for killing vibration. Four of these Isopucks underneath the sub reduced vibration to zero. I could put my hand on the floor next to the sub and feel nothing except the sub itself. Very impressive.