Aluminum sliding doors 70, 90 series series two, residential aluminum sliding doors inside the 70 series. Series number indicates the number of structural dimensions of the door frame thickness mm. Aluminium sliding window with 55 series, 60 series, 70 series 90 series four. Series selection should be based on the window size and the local air pressure value may be. As a closed balcony aluminum sliding Windows should not be less than 70 series.