Here's what other sites are saying:
Designed to help control and balance the feet, these absorb shock, reduce arch compression and improve overall comfort. For a perfect, customized fit, you'll need to immerse these in hot water and then bend to desired shape. Made of moldable plastic and topped with RUBATEX(R) closed-cell neoprene impregnated with nitrogen bubbles and covered with multi-stretch fabric. Soft arch cushions absorb impact, shock and side-to-side friction. 3/4 length allows for extra toe room in tighter-fitting shoes. One pair per package. These offer stronger, more complete support than Spenco Arch Cushions.