The 21A wooden shelf support is a piece made of Zamak, providing strength and durability similar to steel. Its shape is square to support a horizontal wooden panel and is installed by inserting its dowel into the closet. The dowel from which it is held is 5 mm in diameter by 8 mm in length and the area where the wooden panel is placed is 10 mm wide by 12.5 mm long. It features a nickel-plated finish that provides protection against rust and corrosion and is also available in a 1,000-pack.