This is a pair Symposium isolation shelves They are made to the same dimensions and with the same materials as the very expensive Symposium shelves. I got the building instructions from the Audio Asylum site in the USA. They are made of constrained layers using sheets of Stainless steel, fibreboard, plywood & a special polymer material similar to polystyrene. Measure 380 X 590 X 80
They are suitable for isolating amps or cd players etc from air borne vibration.They really do work but I no longer need them. Cost me $300 in materials alone to make.
Picture only shows one but the other is identical.