As can be seen from the above, your climate, type of house and floor on which the apartment is located very strongly affects the choice of the window. In addition to the double -glazed window and frame, the type of reinforced insert affects the quality and specialization of the window. This reinforced insert is inside the profile and determines its strength. There are three types of inserts from which it is easy to understand how they look. These are P-shaped, M-shaped and o-shaped inserts.