12 point head bolts description: 1. Diameter: M6 through M20, 1/4" through 1-1/2" 2. Thread: Metric Coarse 4G6g 3. Surface finish: Natural color, black oxide 4. Grade: Carbon steel 8.8 5. Steel grade 12.9 for 6 point flange head screw available At PROSPER we strive for perfection. To us perfection means top quality and on time shipment. We specialize in short-runs enabling our customers to purchase minimum quantities of Products with economical price. We monitor the progress of each part from initial order, Through production to shipment. Meanwhile, we tightly control producing schedules to Assure in-time delivery. Customers are at the center of everything we do. We are dedicated to improving our customer's Performance by delivering unparalleled value and innovation service. We also perform strict Inspections from incoming raw material to the final products to assure our clients of good Quality.