Silver PVC String Tags - 3/8"x 3/4" are ultrasonic-proof when used with a permanent marker. Sold by box of 1000. Available in different dimensions.
AVERY The Mighty Badge by Avery, 1 x 3 Silver Name Tags, 10 ID Badges, 80 Inserts for Laser Printers (71206) : Office Products
Labels & Tags — PERRIN