PPS flues: flues made from self-extinguishing polypropylene (thickness 2 mm) with a diameter of 80 mm. These flues can be used for venting flue gases (max. “Txx” 120°C) produced by gas-fired condensing boilers. The flues are made with “male/female” couplings and are fitted with triple lip EPDM seals on the female coupling. The range also includes flexible flues in 50-m rolls. By cutting the flue every half meter (or multiples thereof) it is possible to obtain made-to-measure flexible flues fitted with both a “male” and “female” coupling.