【Product Parameters】Material:Zinc-plating steel. Spring lengh: 5.5 inch,For detailed data, please refer to our second product image. Wire diameter:3mm. Active coil Number:28. 【Explanation】Please measure your spring size and compare it with the product size marked on our second pictures to determine if the spring is suitable for you. 【Spring End Structure】One end of the springs is semicircular, which is easy to install; One end is an eccentric circle with higher tensile strength. 【Waist Drum Springs】These trampoline springs have better elasticity and strength than ordinary straight springs, and can meet the requirements of heavy trampoline.But you need to measure your trampoline size to determine whether the spring size is appropriate. 【Replacement Trampoline Springs】Excellent trampoline replacement springs.Nevertheless, you still need to measure the size of your trampoline to confirm if our springs are suitable for your trampoline. 【After Sales Guarantee】If the trampoline springs you purchased breaks within 1 year. Ansersto heavy-duty trampoline springs are made of Zinc-plating steel, they are cold and crack resistant, unbreakable and anti-rust, have excellent resilience and durability, will be perfect choice for your replacing or assembling.Please check after receiving the product. We pay attention to product quality and customer's shopping experience. We are a company specializing in the sales of sporting goods including trampoline accessories.No matter you have any questions, we will answer you at any time.