With a Tilt and Turn window, the sash opens inwards and the window functions are accessed by moving the handle into different positions.
When the handle is positioned pointing down, the sash is locked, using the numerous locking points all around the frame.
If the handle is moved to the horizontal position, the window tilts slightly into the room, providing excellent ventilation even when it's raining.
With the handle pointing up, the window turns fully into the room, just like a door. This is ideal for cleaning the outside of the window, and also gives a large ventilation area for use in periods of warmer weather.