4-way stretch fabric with silpure antimicrobial helps prevent blisters while controlling odor Spencore material a 5/32 inch layer of this material absorbs shock and impact to provide intense comfort and cushioning Lightweight polysorb polyurethane foam provides heel cupping and contoured arch support Spencore heel plug provides extra cushioning and shock absorption in the heel Contoured, flexible support. walkers, runners and joggers seeking additional comfort and cushioning. consumers who want targeted shock absorption for rear foot impact. A120507.