A soldier from Headquarters and Headquarters Company, 301st Maneuver Enhancement Brigade, checks her mask for a proper seal at the Chemical, Biological, Radiological and Nuclear training held at Joint Base Lewis-McChord, Washington, January 21, 2017. The purpose of the training was to familiarize soldiers with the M50 Joint Service General Purpose Mask, and to ensure that they are prepared to respond to a CBRN incident or attack.