From the website:
"The Fat Pad is a mini Symposium platform- only 2" by 3" (5 x 7.6 cm), and 7/8" thick (2.2 cm) with tops and bottoms that are layers of precision laser-cut, polished stainless steel. Their interior consists of 3 constrained layers, including a 3/4" (1.9 cm) thick foam center section banded with textured vinyl edgebanding. The foam section is the same thickness as the Super Plus Platform. A Fat Pad can be considered an "expanded" Point Pod, since it is identical save for its thicker, banded foam center."
I have used them under preamps, power conditioners and turntables.
http://www.symposiumusa.com/fatpadzetup.htmlI think 3 can handle some good weight but probably not heavy amps. That's why there are ultra padz.