Helo Dunker Training

Marines with Echo Company, 2nd Battalion, 5th Marine Regiment, 1st Marine Division, conduct underwater egress training at the Water Survival Training Center on Marine Corps Base Camp Pendleton, California.
The training, also known as the helo dunker, is a lifesaving course that provides all service members with the skills and confidence to successfully and safely evacuate a submerged helicopter.
(U.S. Marine Corps video by Lance Cpl. Anthony Alvarez)