Ideal Security's Window or Patio Door Security Bar with Child-Proof Lock adds safety, security, and acts a visual deterrent to your window or sliding door. Made of aluminium, the security bar easily slides from 15.7-inches to 26.75-inches. The bar is designed to be installed on narrow patio doors and medium-sized vertical or horizontal hung windows without cutting. It also allows the door or window to partially open while being locked in placed, which is ideal for ventilation and housing an in-window air conditioner.Contrary to pressure mounted bars, this security bar won't pop out or loosen over time. Installation is quick, simply fasten the enclosed two saddles with screws or double-sided tape provided on the window or frame, vertically or horizontally, and slot in the security bar. The child-proof anti-lift lock is designed so that children can't open the window or door without supervision. It can also be removed quickly, providing a quick and easy escape in case of emergency.