Quality Materials304 stainless steel rings made of high quality raw materials. No rust, corrosion resistance, high hardness, non-toxic and pollution-free environment. Suitable for any scene. . Easy InstallThis product has 4 holes on the mounting surface with bolts to ensure sturdiness and safety, which works well in practical use. Pre-drilled expansion screws for concrete application installed in just minutes. . Spring carabiner hookVersatile fastening, rigging and anchoring material - Allows quick connection / disconnection of ropes, chains, straps Opens and closes smoothly because the spring-loaded door makes it easy to attach important items. . Widely application For indoor and outdoor use, applicable to concrete ceilings and wooden beams, the best anchoring solution for all suspension straps and resistance trainers , Hammock Swing kit, Olympic rings, battle ropes, yoga swings and boxing equipment. .