These screw cap covers by Prime-Line Products are constructed of plastic and come white in color. They feature grooved shafts to improve gripping strength and hold, and they fit into the drive head grooves of metal Phillip's head fasteners. They feature a 1/2 in. outside diameter head and a smooth, contoured head. These caps have a low-profile design and easy to install. Using screw cap covers like these helps to add a beautiful finished look to cabinets, shelves, hardware installs, tables, chairs, and many other applications.