EXVENT 144 SMOKY GRAY J-VENT | The louvered exhaust vent is used to vent dryers and bathroom exhaust fans. The unique design includes a built-in grid to prevent bird intrusion and a 10" long metal tube that can be used for extra thick walls. Design allows for open or closed flaps. Manufactured with ultraviolet-stabilized color, minimizing the effects of exposure to the elements. Compatible with all siding profiles. Rich textured appearance. Surface dimensions: 7" x 7". Flange dimensions: 8-1/2" x 7-1/2". J-Channel internal dimension: 3/4" adjusts to 1-1/4". Tube length: 10" tube. Diameter: 4"