chimney knee (chimney elbow knee pipe) are exhaust pipe elements (static, single element bended piece or multi-element adjustable angle knees) for the construction or expanding of flue gas outlet (chimeny exhaust system) from the boiler, stove, fireplace outlet to the chimney inlet. Multi-part elbow element can be set to create a straight flue pipe or be part of the chimney connection with a desired angle. Chimney Elbow allows you to expand installations where simple straight chimney connections are not sufficient or the required angle to the chimney inlet system must have a right angle. Elbow knees and angle knees pipes are made of durable heat-resistant carbon steel resistant to high temperature of the boiler or furnace and are protected by a black heat-resistant paint to protect it against corrosion. Elbow knees and angle knees pipes can also serve as straight pipe connection elements.