INCLUDES - 1 Hanging Chair Mattress with Spring, 1 Stiff Plug Hardware, and 1 Layer. The spring and U-stiff plugs are made of steel, heat-treated, stainless, and corrosion-resistant. Upgraded Kit Layer LAGRET is made of steel, with high durability, excellent temperature resistance, and high hardness. It can effectively enhance lubrication and reduce noise. The spring absorbs vibrations during shaking, plays a cushioning role, extends the chair's lifespan, and makes it more comfortable during movement. WIDESPREAD USE - Suitable for almost all hanging chairs, egg chairs, veranda swings, standalone swings, hammocks, and hammock chairs. SAFER HANGING - With a load capacity of over 500 pounds, the spring meets the daily needs of most families, matching the load capacity of standard egg hanging chairs. EASY TO USE - You can refer to the image for the installation sequence. The pin passes through the support and connects to the spring. You can install it or replace existing ones in a few minutes. QUALITY GUARANTEE - Each product is carefully inspected before packaging. Satisfaction Guarantee If for any reason you are not completely satisfied, you can request a replacement or full refund, no questions asked.