Rheem RTG20151D-1 3" x 5" Concentric 36-Inch Vent, Stainless Steel, Stainless Steel Concentric straight vent length for use with a mid efficiency tankless gas installation. Precision formed gasket allows for easy installation. 35.66 in. in total length. Designed to fit the EcoSense Tankless Gas Water Heater. Product Details: Fast, easy installation, 1 step connection. Leak proof seamless precision formed gasket....