The delivery was fast and well packed. I use the window closer in a homemade Gewächshaus.Der installation was described simply and not as complicated as in the enclosed instructions. As for me, frame and window casement (side) are made of wood, I have the two pre-drilled flaps bzw.an bolted the window sash directly to the frame. After insertion of the piston, the device already worked with a corresponding change in temperature. The adjustment was carried out by rotating the piston (cylinder). I have set the device so that the casement begins about 20 ° C with the opening. When cooled below this temperature, the window is reliably closed by the return springs again. A great design that works without additional energy!