Glazier Products Black Concrete Screws (1/4" x 6", Flat Head, Star Drive) fasten directly into concrete, brick, block, and mortar with no separate anchor required - drill a 3/16" pilot hole 1/4" deeper than screw length and drive in screw. Hardened carbon steel with a ruspert coated black finish delivers corrosion resistance and holding power while blending with dark fixtures, ironwork, railings, and modern finishes. The partially threaded design (1.97" of 1/4"-12 UNC thread) lets the screw clamp material tight to the masonry while the threads anchor in the base. The T30 star drive recess resists cam-out under high torque, so screws drive faster with fewer stripped heads. The countersunk flat head finishes flush with the work surface for clean, professional results on wood-to-masonry connections. Ideal for contractors, glaziers, remodelers, and DIYers fastening sill plates, ledgers, furring strips, electrical boxes, brackets, and fixtures to concrete and masonry. Sold in a jobsite-ready 100 pack.