[1] Used to attach hammock chair springs and other hanging accessories (such as sandbags, hanging plants, etc.). [2] Securely attach hammock chair parts to the swing set so they can rotate and swing without jamming or loosening. [3] Made of high-strength alloy, lightweight and durable—you'll love it. [4] Robust construction, long industrial-grade coil spring, ideal for demanding applications. [5] The spring hook is low-noise, low-tension, and low-vibration. An essential gadget for outdoor products.