4 INCH 100MM Round Soil and Vent Condensation Trap with Overflow - Stop Water Leakage Back in to Your Duct Work - DUCTING Fittings by KAIR Ventilation : Amazon.co.uk: DIY & Tools
125mm Condensation Trap With Overflow | i-sells
Ducting Condensation Trap
Bathroom extractor fan - BMW 3-Series and 4-Series Forum (F30 / F32) | F30POST
Plumbing help - Condensation run off into soil stack - Singletrack World Magazine