For Rivet style exhaust cans. Blind rivets are the best option so you don’t have the drop piece fall in your can and rattle around like marbles. It’s a blind rivet to prevent thay. Also the correct and common size used on all 2-Stroke cans 
Come in pack of 12 . Suggest using an Air/hydraulic Rivet gun. Mechanical Hand rivet pliers are a bit of muscle work. But can be used.