Trampoline’s bottom legs are made of tough steel, which keeps the base in place and lasts longer outside. The legs are equally distributed, and flawlessly disperse the weight of trampoline and those who are jumping onto it. U-shapes are more sturdy and solid that vertical legs.High tension, tightly-coiled springs are found on the inside part of the net to ensure security. Also, we have tested springs that are strong for smooth and consistent bounce.