The QUANTAPANEL 706-SL Architectural Low-e Storm Window installs on the exterior of an existing window on the blind stop. The attachment flange is positioned perpendicular and in the center of the box-beam frame, providing an exceptional, low profile, more fully integrated installation. This 2-track system has removable sash and removable screen in the outer track, and an inner sash that opens horizontally to to allow for fresh air ventilation. The QUANTAPANEL 706-SL can be ordered in a 2-sash or 3-sash configuration. All sashes remove to the interior for cleaning and maintenance. The low-profile design integrates with the existing window providing an unobstructed view of the existing primary window. An optional interior handle on the lower, operable sash provides simpler operation when opening and closing the window. The QUANTAPANEL 706-SL Architectural Low-e Storm Window is available in standard or custom colors (185 colors to choose from)!