CITRAGAS Flues: AISI 316L BA stainless steel single-wall flues (thickness 0.5 mm) produced in diameters of 80 – 300 mm included. These flues are characterized by a special interlocking joint system which guarantees quick and easy assembly. The two “male/female” couplings simply need pushing together and twisting slightly to achieve a stable joint. Consequently the interlocking joint does not need a locking clamp. Clamps can be used and are necessary on all overhanging joints (i.e. those after the last support bracket). Furthermore, Citragas flues can house a triple lip silicone seal in a specially created seat on the “female” coupling.