Jump Prep Marines apply camouflage paint before a high-altitude, low-opening, or HALO, jump for training exercise Valiant Shield on Andersen Air Force Base, Guam, Sept. 17, 2016. A HALO jump involves jumping from a high altitude and opening a parachute at a low altitude. Valiant Shield is a biennial, U.S. only field-training exercise with a focus on integration of joint training among U.S. forces. Marine Corps photo by Sgt. Justin Fisher SHARE: Download: Full Size (0.67 MB) Credit: Sgt. Justin Fisher VIRIN: 160916-M-QA315-073A.JPG Photo Gallery