4 Pcs Left Door Opener--This must-have child safety device is designed to limit window opening to 100mm, prevent children or pets from falling or missing, ensuring their safety. Automatically Re-engages restricted position: It can be detached to facilitate fully opening the window, It automatically re-engages restricted position upon closing the window, convenient to use. Durable 304 stainless steel: They are made Made of 304 stainless steel with excellent corrosion resistance, high hardness and rust protection, to prolong its service life. Easy to use - just need a screwdriver to fix it to the window, finish the facility. (screws included) Perfect Application: This window reducer is an ideal choice for home, preschool, security and more. Color: Silver Size: As shown Shipping Quantity: 4 pieces