Countersunk POP Rivets Alu + Steel Open Blind Rivet 2.4/3/3.2/4/4.8/5/6/6.4mm

Head type : Countersunk. Simply drill a suitable hole and insert the blind rivet head into it, use rivet gun to pull the mandrel through. Then, you can lock the rivet in place and get a strong fastening.

eBay