Set of 4 window restrictor locks that limit how far a window or door can open while allowing ventilation. Steel cable design resists bending and wear, with a reliable locking core for added security. Key features Durable construction: high quality materials and steel cable resist pressure and are not easily damaged. Cable size: 19 cm steel cable with a flexible profile; effective restriction distance about 18.5 to 19 cm. Lock and release: special limiting design holds the cable in place to restrict opening; use the included wrench to remove one end of the cable and fully open the window when needed. Installation ready: each unit includes self-drilling screws and a wrench. Cable body installs with a screwdriver or drill. Broad compatibility: suitable for PVC, aluminum, wood and composite doors and windows. Works on double hung, casement and sliding windows, as well as balcony and interior doors. Improved security: unique locking core increases resistance to tampering and helps control access. Benefits and problem solving Prevents windows from opening wide enough for falls or unwanted entry while still allowing fresh air. Simple mechanical operation provides a predictable limit without electronics or ongoing maintenance. Compact design adapts to different frame materials and window types, making it practical for homes, rentals and childcare areas. Typical applications Limit opening on a bedroom or playroom window to reduce risk of falls. Allow partial ventilation on a balcony door while restricting full access. Control opening on ground floor windows in rental units or guest rooms. Package contents 4 restrictor locks, each with mounting screws and wrench.