You are bidding on approx 4 lbs (roughly 250 - 300 pcs.) Truss head (or mushroom head or brazier head) rivets, with a 3/16" x 1 1/4" shank, made of what I'm pretty sure is mild steel. Some surface rust is present but they should clean up pretty easily. IIRC these were originally purchased for use in antique car restoration, but could be used for just about anything from steampunk gadgets to reproductions of medieval helmets. I believe these would be well-suited for riveting wood slats to a steel frame, as long as the wood isn't too thick. Items shown in pictures are what you will receive.
Dude, the quarter is not included.