Material: stainless steel shell, all imports of wire rope (diameter 1.1mm) outsourcing of high-strength resin material, laser technology LOGO. Thickened high stretch winding spring. Tip; pull the wire must not use excessive force, likely to cause feedback spring failure. How to use: key ring placed on the belt, keys on a key ring, stretching out the use of the door. When not let go, automatically rebound to the waist, avoid frequent random throw put the key cause is lost