Service members from the San Francisco-based Coast Guard Port Security Unit 312 test the fit and function of their M50 Joint Service General Purpose Mask during Exercise Pacific Blitz 2019 (PacBlitz19) in Port Hueneme, California, March 6, 2019. PacBlitz provides an opportunity for Coast Guard service members assigned to PSU 312 to train alongside other members of the armed forces through realistic and relevant training necessary for effective global crisis response. (U.S. Coast Guard photo by Petty Officer 1st Class Matthew S. Masaschi).