The ventilation chimney cowl is the easiest, simplest and most budget-friendly all-rounder of all possible vertical air exhaust ends in installation systems built with round ducts and fittings. The product is available in 2 different sizes, each for a specific diameter range. The product is installed by bending down the 3 or 4 legs to fit the connected spiral duct, inserting the legs down to the stop, and fastening them with WGO screws or blind rivets.