Twin-thread PZD countersunk screws. Yellow zinc passivated for corrosion resistance. Includes sizes 3 x 16, 3 x 20, 3.5 x 25, 3.5 x 30, 4 x 30, 4 x 35, 4 x 40, 5 x 40, 5 x 50, 5 x 60 and 5 x 80. Handy storage case with individual compartments