The Greek company Alumil is leader on the Balkans. It continuously develops and improves the old profile systems with interrupted thermal bridge. Aluminium joinery with Alumil profiles has been produced for more than 15 years in Bulgaria. The development of the profiles is reduction of the coefficient of heat transition through enlargement of the polyamide link between the external and internal aluminium parts and change in the configuration of the middle insulation for reduction of the convection. In that way during the years the following profile systems have appeared consecutively: M9650, M11000, M11500.