The Nasal Ranger, a field olfactometer advertised as allowing users to conduct “complete odor monitoring, regulation, enforcement and documentation,” has been employed by officials in Denver and Las Vegas. Correspondence obtained by Motherboard via a freedom of information request between officials in one Michigan city and St. Croix Sensory, the company that manufactures the Nasal Ranger, shows that cities are interested in the device for one smell in particular: weed.