These vibration isolation blocks are an inexpensive way to reduce the slight noise and vibration associated with the operation of any blower including those in furnaces and air handlers. Simply set your furnace or air handler on top of four or more isolation blocks and the composite foam center absorbs the vibration. These blocks are more structurally sound than cork and are not affected by oils or chemicals. They are 3 inch squares and 7/8 of an inch tall.