Main Size. Standard M12 expansion bolts with 120mm length, and the ring Inner Diameter is 29mm. Materials. Made of premium 304 stainless steel, provides a rust protection and precise size. Installation. Suggested a 16mm Dia. hole for drilling, and tight the anchor bolt with a wrench after putting the screw. The bolt transfers forces to the sleeve, with the expansion of sleeve, a solid connection has been built between a concrete wall and the wedge anchor nut. Application. Fit the concrete wall or masonry, for hanging or lefting the super heavy things like a big shelf. It's durable and reliable. Details. The eye type is drop forged eye, such eye bolts are designed to attach a securing eye to a structure and then tie to ropers or cables. Screw Size: M12Overall Length: 120mmEye Nut Height: 47mm Inner diameter of the ring: 29mmSleeve Inner Diameter: 12mmSleeve Length: 50mmSuggested Hole Size: 16mm Dia.Total Weight: 392gMaterials: 304 Stainless SteelApplication: Concrete and masonryPackage Content:2 x pcs M12 x 80 Expansion Eye Bolt