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 TierraCast's 4mm rivets and all 3 sizes of eyelets to embellish, reinforce or adjust thickness of your leather designs or other cold connections. TierraCast Safety Compliance Info.