Torx flat countersunk head carpentry wood screw with under-head serration, made of hardened carbon steel. The serrations under head cut wood fibres while tightening, so the head sinks smoothly without wood splitting or surface fuzzing. Torx star drive transfers high torque and avoids driver slipping. Type17 cutting point enables easy self-tapping into hardwood, softwood, MDF and particleboard without pre-drilling. Widely used for timber construction, decking, furniture, cabinet and carpentry works. Sizes 3.5~6.0mm, length 20–160mm. Yellow zinc / Ruspert coating optional.