Employees of the U.S. Secret Service, among the federal workers going without pay during the government shutdown, have designed a memento commemorate the occasion.

Secret Service personnel used their own money to create challenge coins – small medallions traditionally traded among military units – in recognition of the weeks they’ve gone without pay during the shutdown. CNN was the first to report on the coins.

“Don’t worry, you’ll get backpay,” is printed on one side of the coin with an image of the nation’s Capitol with a “closed” sign. The other side said “United States Secret Service” and “Essential Personnel.”

Photos of special challenge coins being distributed among Secret Service personnel and their families, expressing frustration at the requirement they work without pay because of the government shutdown pic.twitter.com/0Toz1zpiIV — Jake Tapper (@jaketapper) January 23, 2019

The Secret Service falls under the Department of Homeland Security, one of the unappropriated agencies where employees are going without pay during the shutdown that began on Dec. 22. Nearly 6,000 for the service’s 7,200 employees are working without pay; another 1,200 are on furlough. All will receive back pay once the government reopens, though when that will happen remains unknown.

The Secret Service protects the president and his family, as well as embassies and foreign dignitaries within the U.S. and abroad. It also investigates some financial crimes.