The plastic access panel is designed to provide easy access to walls & ceilings. The high impact styrene plastic with U.V. stabilizers will not fade or corrode. All units except the 14x29 are hinged with a removable door panel feature. White Finish. 24-7/8"W x 24-7/8"H Outside Flange Dimensions. 22-1/8"W x 5/8"D x 22-1/16"H Return Flange Dimensions.