Abstract: A security closure device to protect a building opening and a closure member. The device includes a main security panel and a narrower secondary security panel that are hingedly mounted to each other. The side of the main security panel opposite to the smaller security panel is hingedly mounted to a security casing assembly inside the building defining the protected opening. A user can readily unlock the narrower panel from the casing assembly from inside the building without requiring a key or combination. From the outside, a key or combination is required. To open the inwardly swinging security closure, a user opens the closure member a sufficient distance determined by the width of the secondary panel to unlock it. The angular travel of the secondary panel with respect to the main security panel is limited by a stopper assembly.