Easy to install: No additional tools needed to install, it has a hex key in each window lock and is locked to the rail. Material durable: Sturdy, robust and well-designed, with an aluminum alloy frame and fully utilized stainless steel screws. Versatile: easily adaptable to most environments, keeping windows partially open and deterring burglars, anti-theft locks prevent children from falling and protect your family while improving air circulation. feature: Dimensions: 6 x 2.3 x 1.9 cm Material: 6061 aluminum alloy Quantity: 4 pieces Package included: 4 x double sliding window locks with 4 keys Note: Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement. Sold by-Minnanxin