This die becomes shorter and wider until it can never expand anymore due to container wall restriction. That’s when the aluminum material starts forcing its way out through the die’s orifice and form a particular profile.
Their use is quite limited in residential properties as they do not provide much ventilation. However, they may be worth considering if you have a very small WC or a temporary room like a cellar or storeroom.
Profilati Alluminio manufactures and ships worldwide – thus in the U.S. too – various types of aluminum extrusions also with extremely small dimensional tolerances: among them, aluminum window extrusion profiles.