Minerallac Cully Tapcon Concrete Screw, 1/4 in Diameter, 2-3/4 in Overall Length, Hex Washer/Slotted Head Drive, Steel, 3/16 in Drill, Blue Climaseal Coated, Applicable Materials: Block, Brick and Concrete, Patented Advance Threadform Thread, 0.308 in W x 0.187 in H Head