Army Staff Sgt. Dwight Harris, right, checks that Army Pfc. Nsilo Q. Jenkins' M40 field protective mask is functioning properly during chemical, biological, radiological and nuclear sustainment training on Joint Base Elmendorf-Richardson, Alaska, July 16, 2015. Harris, a CBRN specialist, and Jenkins are assigned to Company C, 307th Expeditionary Signal Battalion. Army Staff Sgt. Dwight Harris, right, checks that Army Pfc. Nsilo Q. Jenkins' M40 field protective mask is functioning properly during chemical, biological, radiological and nuclear sustainment training on Joint Base Elmendorf-Richardson, Alaska, July 16, 2015. Harris, a CBRN specialist, and Jenkins are assigned to Company C, 307th Expeditionary Signal Battalion. SHARE: Download: Full Size (1.883457 MB) Tags: Photo Essays Credit: VIRIN: 282793-I-JGL84-840.jpg Photo Gallery