Plastic hollow wall anchor consists of a cylindrical body with four anti-rotation fins. The hollow wall anchor is like a wedge or expansion type concrete anchor more or less. The anchor can provide power for light to medium loads in all walls. It's used in thin paneling, gypsum board, plasterboard, and many other hollow base materials. Based on the grip range, the anchor comes in three different sizes: PHWAA, PHWAB, PHWAC. It's corrosion resistant because it's made of polypropylene.