Robust steel construction. Galvanized and clear coated for extra weather resistance. Very strong and can be used for a long time. The spring helps to relieve the stress of impact, provides a more comfortable and softer feel and extends the life of your hammock as well as the hammock surface. Compatible with almost all punching bags, punching bags, hanging chairs, cocoons, egg chairs, basket chairs, etc. Rated spring capacity of more than 300 kilograms. Contents: 2 x carabiners. Wire diameter: approx. 7 mm, length: approx. 108 mm.