FORSPE1100Y Spectre Advanced Screw Set, 1100 Piece Spectre by Forgefix incorporates a long list of advanced screw features, often only found in premium screws, into what we've named advanced multi-purpose wood screws. They feature a countersunk, pozidrive compatible, recessed head. Fully threaded, up to 50mm, with a sawtooth thread, to prevent splitting and reamer to prevent jacking (50mm and above) They are also surface hardened with a quick start type 17 slash point. The screws have a zinc yellow passivated finish for excellent resistance to corrosion. Zinc yellow passivation process of electroplating is similar to the 'galvanised' and 'zinc plated' processes, with the addition of a yellow dye. It offers an aesthetically pleasing finish. CE approved for use in load-bearing timber construction. The tough compartment case contains: 130 x Spectre PZ Compatible Wood Screws 3.5 x 25mm. 190 x Spectre PZ Compatible Wood Screws 3.5 x 30mm. 130 x Spectre PZ Compatible Wood Screws 4.0 x