Hoffman APWK2420H, Hinged Window Kit, 22.28x18.28, 24.00x20.00x1.49, Steel/GrayFor use as a viewing window where access to components mounted behind the window is required. Window is .25-in. (6-mm) clear acrylic. Easily mounted by drilling the appropriate mounting holes. All mounting hardware is provided. Continuous gaskets on all openings maintain UL Type 12 integrity. Finish is ANSI 61 gray polyester powder paint.