The TIMCO Concrete Screws Flat Countersunk Silver – 7.5 x 100 provides a rapid and effective light duty anchoring system for fixing into concrete, brick, stone, concrete block and wood. This through fixing offers a single solution that replaces traditional fixings such as nylon frame and hammer fixings. Features include a TX30 drive recess to reduce driver wear and prevent camming-out, serrated V-threads for optimum insertion into all masonry types, and zinc plating for increased corrosion resistance. The high-low thread design on the first 30mm aids insertion and reduces torque, making these screws ideal for fitting windows and door frames.