Check the listing for details. US 2nd INFANTRY DIVISION CHALLENGE COIN + MATCHING EMBROIDERED PATCH. Condition: New. Listed at 17.98 USD. Besides using these military coins for challenging, they are also used as rewards or awards for outstanding service or performance of duty. As such they are used as a tool to build morale. In the context as they are used by the modern U.S. military, the tradition probably began among special forces units during the Vietnam War.