Durable 7.5mm T30 countersunk masonry screws used to directly fix window frames to the masonry, concrete and lightweight block. Available in bright zinc plated. Lengths range from 80mm to 180mm – all boxed in 100’s. A pilot drill of 6mm or 6.5mm diameter is required. To complement the masonry screws why not use the Torx30 x 25mm driver bits?