Application: Window security locks can be used on aluminum, wood, and vinyl windows, suitable for vertical and horizontal sliding windows, singlehung windows, and doublehung windows or doors. They are common locks for homes, public buildings, etc. that require sliding windows. Note: Before ordering, please refer to the picture for size and compare with your needs. Advantage: The lock is made of zinc alloy, which is hard and not easy to break, wearresistant, corrosionresistant, and rustresistant. Strong and durable. Cam Action Hook Design: Features camtype locking mechanism designed to grab and pull the keeper and meeting rails firmly together, providing tighter seals and increased security. Package Includes: 1 Set Slider Window Latch locks with 4 pcs Screws. The installation operation is simple. Use an electric drill to drill a hole on the side of the window, and then tighten the screws with a Phillips screwdriver to lock the metal sash lock.