The DuraVent 5GVL90 5" Inner Diameter Type B Round Gas Vent Pipe is a silver-colored, UL-listed vent pipe made of aluminum and steel. It is designed for use with DuraVent 5 inch round gas vent models and is suitable for chimney applications. With a diameter of 5 inches and a twin wall construction, this vent pipe is a reliable and durable option for your heating and ventilation needs. It is also California Prop 65 compliant, ensuring safety in its use.