Security bolt, surface-mounted, model crr12, made of steel with a gray finish, 86 b/50 mm, with 3 serrated keys, 86 mm plate and 50 mm round cylinder, to reinforce security by installing on any type of door, in addition, being reversible, it is not handed, the interior operation is carried out by means of a button, while the exterior is carried out by means of a key through the cylinder