The United States Postal Service has released a set of Forever stamps honoring members of the United States military that are often overlooked, NBC5 reports. The special military working dog postage stamps showcase the canine heroes that work alongside service members and put their lives on the line to save others.

According to the USPS, the new stamp collection features four breeds—German shepherd, Labrador retriever, Dutch shepherd, and Belgian Malinois—that are commonly used as working dogs by the U.S. military. Each block of four stamps features the four dog breeds, adding up to 20 stamps per booklet.

The dogs fill various needs: German shepherds can be trained to sniff out bombs, while Labs are often used in search-and-rescue missions. "Brave and loyal military working dogs are essential members of America’s armed forces," the postal service said in a statement.

Working dogs have served with U.S. soldiers in both World Wars, the Korean War, the Vietnam War, and the wars in Iraq and Afghanistan.

USPS

Each postage stamp was designed by Greg Breeding, the art director at DKNG Studios. They feature stylized illustrations of the dogs against a white star on either a red or blue background.

The stamps debuted at a special ceremony today, August 1, and they're now available to purchase from the USPS online store and from your local post office. Collectors can add the booklet to their sets of Forever stamps that have been released in the past few years, which include stamps honoring Sesame Street and Mister Rogers.

[h/t NBC5]