Surface-mounted security deadbolt, model crr10, made of nickel-finished steel, 86b/50 mm, with 5 keys and chain, 86 mm plate and 50 mm round cylinder, designed to enhance security by installing on any type of door. its reversible design allows for easy access - internal operation is via a button, while external operation is controlled by a security key through the cylinder. it also features an anti-bumping system