It’s no secret that manufacturers sometimes take a very expensive profile, but already in the production process they use the most simple combination. As a result, it seems like a pretty good German profile, the most solid trademark, and the buyer likes the product outwardly. But during the operation, suddenly a number of different deviations are already revealed, for example, a handle is turning very tightly and with a creak, there is no very dense press between the frame and the sash. Moreover, everyone squeaks and creaks everything.