Suitable for the Viessmann residential gas boiler range (Vitodens 100-W & Vitodens 111-W). The flue makes it easy to get around obstructions, and are quick and easy to install. The Vitodens Vertical Flue Kit consists of: 500mm pipe and an external outlet. Extensions can be added as required NOTE: Flue system is dependent on boiler output, flue bends and fittings, straight lengths and flue routing.