Turn the handle upwards, and the upper part of the sash tilts slightly to allow safe and easy ventilation. The opening cannot exceed 4″ (130 mm) and the window remains open for as long as you like, without the wind ever causing it to slam shut.
Want to ventilate your room thoroughly or open your window as wide as possible to circulate freely indoors and out? Simply turn the handle to the horizontal position, and the sash hinges on the side to offer a larger opening.
Turn the handle down, and the tilt-and-turn window will be hermetically sealed. No air leakage, no way for burglars to get in.