In the double-hung window the sash opens with a down-top sliding movement next to the fixed sash. 
Molaro manufactures this product even with the tilt opening and the sash is balanced in order it can stop on each position.

In the Molaro bifolding doors the sashes have a special folding and sliding opening.
This system is perfect for the areas where the client wants to enhance the external landscape view, in not particularly cold areas.