GRK Star Drive driver bits come in 3 sizes to work with all of the GRK fasteners we carry. The bits are colored coded and come in 1" or 2" lengths. The 2" driver bits feature a quick release groove. Yellow driver bits fit #4 size R4 screws and #8 trim head screws. Red driver bits fit #6 and #8 size R4 screws and #8 cabinet screws. Green driver bits fit #9, #10 and #12 size R4 screws and #10 RSS screws. Get a grip with Star Drive screws!