Made in the USA from stamped brass! TierraCast® silver plated brass 6.35mm micro washers. 2.4mm hole. Silver plate is a thin surface layer of actual silver. Use these washers with rivets and eyelets to add extra security to your leather designs. Place the washer on the back side of the leather to prevent the rivet or eyelet from slipping through the leather hole. TierraCast Safety Compliance Info.