Thicker gauge steel, more coils and wider cone. Reinforced trampoline springs not only replace your worn out springs, but also improve the complete bouncing experience High: Premium heat-treated galvanized steel, 6.5 inches long and 3 mm in diameter, are made for years of jumping. Advanced Tension Mechanism: Springs are designed with an advanced tension mechanism with a new cone design for a greater jumping experience. Recover Your Old Trampoline: Upgraded trampoline springs are designed to replace rusty, worn out and dangerous springs on your trampoline and return the bounce to your old, sagging mat. Increased Curvature for Excellent Hold: Curved for better hold. Jump and bounce without worrying about the springs coming loose. Go ahead and let loose!