During water survival training at the station pool, a Marine from Combat Service Support Detachment-36 (CSSD-36) floats on his back in deep water during swimming qualification. He is wearing helmet with chin strap, flak jacket, H-harness, and the all purpose, light weight, individual carrying equipment (ALICE) pack. He grips the sling of the M16A2 rifle with his teeth so that both hands are free to tread water.