What you get: 4 pieces of child safety window locks with corresponding set screws and keys. for Sturdy Alloy Structure: The window limiter is made of high-quality aluminum alloy, durable and not easy to wear. White powder coated finish to match perfectly with your doors and windows. EASY TO LOCK AND UNLOCK: This window restrictor has a special locking mechanism design that provides 11 to 16 cm of restriction and lets in fresh air. After opening one side of the window lock by turning the key, the window can be fully opened. Wide application: These multifunctional window safety limiters are suitable for doors and windows that open inward and outward, such as room doors, windows or balcony windows, etc. Also a great safety feature for your RV and worth exploring!