Introducing the Propel 15' trampoline with enclosure. The safest, bounciest trampoline on the market! What makes a Propel Trampoline the best All Propel Trampolines have a number of advanced safety, stability and durability futures, including:Propel Trampolines 15' Trampoline with Enclosure Features: Impact absorbent response system. The enclosure attaches to each of the 6 padded enclosure poles with a high strength bungee. Because of this, if your child hits the enclosure they will be presented with a sturdy yet soft and absorbent response, not the brick wall effect you get from the other brands. Sure lock safety pad. The thick safety pad is kept in place by 6 grommets which the corresponding enclosure poles feed trough before attaching to the frame. This keeps the pad in place in any weather. T Bracket technologies. The advanced T bracket system prevents the frame from twisting while increasing overall stability. 108 Springs. Propel Trampoline'