The Model VM129 90-degree Steel Street Elbow Fitting is made from central vacuum grade 2-inch outside diameter steel tubing with a male connection on one end and a female connection on the other end. Local building codes in some areas may require that steel tubing must be used for the central vacuum’s exhaust system. The exhaust system routes the exhaust air from the central vacuum power unit to outside the residence. This fitting provides a 90-degree connection. AirVac steel tubing and fittings can be connected using Pliobond® Brand Steel Tubing Adhesive.