Replace old, compacted underlayment and restore the spring to your carpeted aerobic floor. Cross-linked, closed-cell EnduroFoam is characterized by its incredible resilience, and can be installed over any subfloor, with virtually any carpet over it. Rolls are 4' wide and cut to customer-specified length. The system consists of two layers of foam permanently bonded together. The 1/4" four-pound density top layer provides lateral stability to prevent injuries, while the 1/2" two-pound density bottom layer provides maximum impact absorption. This combination gives the cushioning needed for floor exercises and the "bounce" required for aerobic dance. A special release adhesive is available so you can replace your carpet while reusing the underlayment.