Wallboard finishing box designed for perfect finishing of butt and flat joint edges, whether applying a first coat or a final finish. Easy operation with a fixed hinge for quick opening and cleaning, and a back for better hand manipulation. Constructed with hard coated anodized aluminum casing, making it , and wear for long-lasting use. Standard flat type size, compact structure, compatible with all mainstream of plasterboard flat box handles. Easy to open by turning the screw counterclockwise, facilitating installation and removal, ideal for home wall painting and finishing.