Professional Grade Quality, Durability, Genuine Solid Brass Material, and a Superior Finish is what differentiates this 6" classic sliding surface bolt by idh by St. Simons of California. Sleek and smooth sliding, this product is designed with a tension spring on the bottom of the bolt so the surface cannot be damaged or marred. It is quite versatile, with two types of keepers (strikes) provided so that it can be surface or mortise mounted. Install it on your screen doors, storm doors, cabinet doors, windows, and anywhere else that additional security is desired. idh by St. Simons offers 6 lengths in this series of surface bolts: 1-1/2", 2", 3", 4", 6", and 8".