The outer stopper can be used through the tightening bolts of seat pins and seat clamps. For use with 0.3 inch (8 mm) hole diameter. Hole Diameter: 0.3 inches (8 mm); Pitch: 0.8 inches (20 mm); 0.2 oz (6 g); Product design, specifications, and appearance may be changed without prior notice. Thank you for your understanding.