We are very pleased to be able to offer this highly durable, superior grade punching bag. The materials used are a professional strength inner inflatable bag and a strong, but soft, nylon cover. The bag is available in two sizes, 36 inches and 48 inches; with each utilizing a sand weighted base (sand is not included, we recommend obtaining cheap play sand from a gardening center or hardware store). This product is guaranteed for two years of appropriate play therapeutic use. The bladders are made of extremely heavy plastic and made with extra l