2 lbs. Center box attached to filtration wand.
In early history various animals were used to detect the unseen traces left by monsters. This was not the most exact way to detect, however; many mistakes were made (see American Revolution). During the 1918-19 flu epidemic (actually caused by a massive infestation of Invisible Boring Xylums), a Troop in Brazil discovered the science that led to the first Spectrometer.
A data collection device that measures all energies, air samples, etc in an area. That data can help Troop members narrow down monster choices. Standard issue.