Surface-mounted security deadbolt, model crr11, made of nickel-finished steel, 86l/50mm, with 5 keys and chain, 86 mm plate and 50 mm round cylinder, designed to reinforce security by installing on any type of door. its reversible design eliminates handedness, and internal and external operation is carried out via a security key through the cylinder. it also features a cylinder protector and anti-bumping system.