Forgefix Concrete Frame Screw - Torx - Zinc Plated - High Low Thread Specially designed self-tapping masonry fixing. Extremely popular fixing for window and door frames. Also now used as a versatile fixing for many applications in DIY, Joinery, Plumbing and Electrical trades. T30 Torx Bit included in boxed product. Finish: Zinc Yellow Passivated. Virtually stress free, allowing close to edge applications. Torx compatible head screw for increased torque control. High load capacity with interlocking thread into base material. High-Low Thread screws have an excellent holding power in wood due to their alternating high and low thread heights. Through fixing, eliminating the need for marking and re-positioning. Widely used for batten, window and door frame fixing. Suitable for most masonry subtrates including concrete and brickwork. Box of 100 supplied with Bolts, End cap & Torx® bit.