M-21 Remote Sensing Chemical Agent Automatic Alarm (RSCAAL)
M-21 Remote Sensing Chemical Agent Automatic Alarm (RSCAAL) : A two-man portable tripod-mounted, automatic scanning, passive, infrared sensor which detects nerve and blister agent vapor clouds based on changes in the infrared energy emitted from remote objects, or from a cloud formed by the agent. The M-21 is line-of-sight dependent with a detection range up to 3 miles and a field of view of 1.5 degrees vertical and 60 degrees horizontal. It will be used for surveillance and reconnaissance missions and will search areas between enemy and friendly forces