We all love our tilt windows but sometimes even the tilted position is to much open. High winds, rain or just too cold; you want to close the window. Now you're left with no ventilation in your house. Bummer. This simple design fixes that. It makes the tilted window open just a little bit, enough to keep water or wind out but open enough to keep the ventilation going.

Modeled in FreeCAD to fit a MACO Locking Piece Strike Plate SP30 safety lock. Might fit others too. 

Added 4 models, 2 for left hand opening windows and 2 for right hand opening windows. For each there is a choice in 5 or 10 mm limiter. The actual gap at the top of your window also depends on the position of the limiter.

Installation: Tilt open your window, clamp limiter on side of window, just above the strike plate. Push window to almost close and slide the limiter down until it catches the strike plate. Slide the limiter upwards to open the window again. (See .gif for visual guide)

Updates 

22-10-2025 Updated to v2:

• Added small void inside the hook. This creates internal walls which should make the part stronger.