90 Degree Exhaust Elbow Adaptor | Barr Marine 20-0093P90 Degree Exhaust Elbow Adaptor Barr Marine 20 0093P Cast iron elbow with 3 in. ID exhaust hose is designed to couple 3 in. ID exhaust connections to either 3 1 2 in. or 4 in. exhaust connections in marine exhaust systems. Barr exhaust elbow Use where a bend or turn is needed in exhaust system Adapts 3 inch to 3 1 2 or 4 inch Includes adaptor, 6 inches of 3 in. inside diameter exhaust hose and clamps