Sturdy steel construction. Zinc plated and clear coated for added weather resistance. Very strong and can be used for a long time. Spring helps relieve stress from impacts, provides a more comfortable and softer feel and will increase the life of your hammock, as well as your mounting surface.< br />Compatible with almost any punching bag, punching bag, hanging chair, cocoon, egg chair, wicker chair, etc. Rated spring capacity of over 700 lbs. Contents: 2 x carabiner. Wire Diameter: 7mm/0.3"(approx), Length: 108mm/4.25"(approx). Due to manual measurement, there will be some errors. Sturdy steel construction. Zinc plated and clear coated for added weather resistance. Very strong and can be used for a long time. The spring helps relieve stress from impacts, provides a more comfortable and softer feel and will increase the life of your hammock, as well as your sleeping surface. assembly. Compatible with almost all punching bags, punching bags, hanging chairs, cocoons, egg chairs, wicker chairs, etc.