TierraCast® 6.35mm gunmetal plated brass micro washers with a 2.4mm hole. Made in the USA from stamped brass! TierraCast provides affordable, quality components that complement a wide range of jewelry designs. These washers are perfect for adding extra security to leather designs! Place on the backside of your leather to prevent rivets and eyelets from slipping through the leather hole. TierraCast Safety Compliance Info.