Window(S) Available with a selection of Clamp Rings to fit total Wall Thickness. Using the correct size clamp ring is KEY for window installation. clamp ring can be 1/8" off of total wall thickness and still work correctly. Example: 1" total wall thickness = 1" clamp ring 24" W x 12” H Work excellent in teardrop trailers, Rvs, Horse trailers, and Cargo trailers. The black frame and tinted glass with radius corners, give that sleek modern look to your recreational trailer/vehicle. These windows are top quality in today's market. Configuration: Cut Out: 12-1/4” W x 24-1/4” H Outside Measurement : 13-1/4” wide x 25-1/4” H Corner Radius: 3-5/16”