U.S. Marines with 1st Marine Division locate their target points during exercise Garnet Rattler on Saylor Creek Range in Grasmere, Idaho, April 18, 2023. Garnet Rattler is a joint exercise between Marines and airmen to train Joint Terminal Attack Controllers to be more efficient and lethal in a realistic training environment. - U.S. Marines with 1st Marine Division locate their target points during exercise Garnet Rattler on Saylor Creek Range in Grasmere, Idaho, April 18, 2023. Garnet Rattler is a joint exercise between Marines and airmen to train Joint Terminal Attack Controllers to be more efficient and lethal in a realistic training environment.