23L607  up for sale is a big bag 1 pound bag or aluminum aircraft rivets, these measure 0.746 total length x 0.1885  ( just under 3/16 dia) the engagement length is most likely 5/8 the 0.188 area is 0.659  long the head is a button head and is around 0.086  high x 0.341 dia just under  ( 3/8) inch, the bags are marked 1 pound and weigh around that value, looks like 200 or 300 rivets , new aluminum material, package is marked with military NSN 5320-01-298-7674  p/n  MS20426E6-12 rivet solid, buyer to pay calculated shipping and packing to your locations, see our store for more items like this , thank you RWK.