1/4 inch diameter x 1-3/4 inch length. No.1 Choice of professionals. Advanced Threadform Technology. 3/16 inch x 3-1/2 inch Tapcon drill bit included. Concrete, block & brick. Approved for treated lumber. Approvals: ICC Evaluation Service Inc. ESR-1671. Miami-dade county product control approved. Quality control agency: CEL Consulting. www.tapcon.com. Learn more inforamtion www.tapcon.com. Anchors made in USA from Canadian steel. Drill bit made in China.