JumpTastic Trampoline have ASTM certificate, the quality tested by the authority. JumpTastic Trampoline apply U-shaped bottom tubes, all galvanized coated tubes with 1.7in diameter, 0.05in thickness. And it choose premium solid steel structure , fully galvanized steel frame for better resistance to rust and corrosion. The 12ft Trampoline come with 6-U-shaped big legs with 12 balanced contact points for better stability and safety. In addition to solid construction, product details make you feel more safe. 72 galvanized springs are covered with 0.5inch thickness trampoline pad to prevent children injured. The no-gap enclosure system interlocks the jump mat and enclosure net at each spring, 5.9ft height enclosure protect your kids in safe zone. That will eliminating dangerous gaps and giving parents peace of mind.