DOUBLE LOCK DESIGN: Our sliding window locks feature a secure double screw mechanism that attaches firmly to sliding window and door tracks. This design prevents sliding while allowing for adjustable ventilation. Installation is simple with the included hex keys—no additional tools required. The locks come with rubber cushioning to protect your windows from scratches and enhance their performance. COMPATIBILITY AND USAGE: These window locks are compatible with sliding windows, sliding doors, and vertical doors. Measuring 2.4 inches in length, they fit tracks up to 0.4 inches wide with rubber cushioning or up to 0.67 inches without it. Be sure to measure your track for proper fitment. HIGH QUALITY MATERIAL: Constructed from durable aluminum alloy, these window locks are built to last. The anti-rust coating is designed to seamlessly blend with white sliding windows and doors, ensuring long-term functionality and aesthetics. PRACTICAL APPLICATIONS: Ideal for sliding patio doors and glass doors, our locks provide peace of mind by allowing you to open your windows slightly for fresh air without compromising security. They prevent unauthorized entry and can be used in children's rooms to keep toddlers safe from falls. PACKAGE CONTENTS: Each package contains four sliding window locks, complete with rubber cushioning and installation keys. Utilizing multiple locks enhances the security of your sliding doors and windows.