Alde Roof Flue A stream-lined flue for roof mounting, with white powder coating or brass facia. This flue protrudes only 95 mm, and can be installed in roof thicknesses up to 60 mm. Comes complete with hose clips for exhaust outlet and air inlet hose. Requires hole size of ø76 mm. For use with the Alde 3010 Compact boiler.