D Co 1-28 IN Conducted M4 CBRNE Familiarization Live Fire Range on 29AUG2016. This training event familiarized Soldiers of D Co with the operation of their M4 carbine while wearing the CBRNE protection mask.
The M40 field protective mask is one of various gas masks used by the military of the United States and its allies to protect from field concentrations of chemical and biological agents, along with radiological fallout particles. It is not effective in an oxygen deficient environment or against ammonia.
Read more:Wikipedia: M40 field protective mask