Upgraded double glazed locks can be applied to heavy doors or windows for added security. These locks are solid and sturdy, featuring exquisite workmanship with an aluminum alloy frame and stainless steel screws that allow for multiple uses. This package includes double sliding window locks with 4 keys. Approximate dimensions: 6 x 2.54 x 2.4 cm (2.36 x 0.95 x 0.95 inches). Designed for track heights over 1.2 cm (0.47 inches) and track thickness no more than 1.6 cm (0.63 inches). Not suitable for middle tracks. Please measure your window track before purchasing. Easy to install without additional tools. Each lock comes with a hex key and is secured in place by a key-controlled mechanism on the track. Suitable for horizontal or vertical sliding windows and glass doors. Not recommended for plastic window frames. Ideal for various environments, these locks allow windows to remain partially open while maintaining security. They help prevent accidental falls, improve air circulation, and enhance household safety. We stand by our product quality. If you are not satisfied, we offer a full refund or a free replacement.