In materials provided to law enforcement, Fog states that it has access to a “near real-time” database of billions of geolocation signals derived from smartphones. It sells subscriptions to a service, which the company usually billed as “Fog Reveal,” that lets law enforcement look up location data in its database through a website. The smartphone signals in Fog’s database include latitude, longitude, timestamp, and a device ID. The company can access historical data reaching back to at least June 2017.