Lead Wood Screw Anchors are ideal for quick installation of medium weight fixtures in concrete, brick, or block. Use #10 or #14 (1/4") wood screws or sheet metal screws to expand anchor. A 5/16" pre-drilled hole is required for installation. Not recommended for ceiling applications. Warning: this product contains lead known to the State of California to cause cancer and birth defects or other reproductive harm. Wash hands after handling.