Quality material. anti-corrosion and anti-rust, with long service life. The telescopic spring has been tested for tensile strength and started to deform at around 250 , without breaking. The spring helps relieve stress from shocks. The steel spring cushions movements in a light and pleasant way, conducive to relaxation, especially when fixed to a concrete ceiling, the spring reacts gently for pleasant rotating and rocking movements. Easy to mount. Comes with 2 large carabiners, extremely strong thanks to a special hardening process, the carabiner allows quick, simple and secure attachment. Widely used. stainless steel spring for hanging chair, hanging seat, hammock, swing for two or baby swing, for anything you want to attach to the ceiling and need to swing. satisfactory. If you have any questions after receiving the product, please and we will get back to you within 24 hours. If you are not satisfied with the product, we have no problem with a full refund. Note: Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement.