Safety: to prevent children from falling out of open windows. Prevent break-in, it can lock the window when the window is open. 2. Ventilation: Keeps indoor air ventilated and fresh. 3. Appearance: concise and pleasant surface design, solid, the use of high-quality materials, easy to open, suitable for all aluminum sliding doors and windows. 4. Locking does not require a key but open. 5. The secondary lock provides added security when venting or securing your sliding door or window. This item attaches to the bottom edge of the sash or door with a small drilling required. Colour:Silver. Features: Name: Sliding Window Lock. Material: Zinc Alloy. < p>Size: as the picture. Color: silver. Contents: 1 x window lock (includes accessories in the picture). Note: - Measurements being taken by hand, the sizes shown may vary slightly. Thank you for your understanding. - Depending on the brightness and light settings of the monitors, the color of the actual item may be slightly different from the