Most pilots maintain a traditional hard copy, but electronic versions[4] such as the one included with the popular app ForeFlight[5] are allowed. Flight hours are recorded in 0.1 hour increments, which correspond to the resolution of a typical Hobbs meter, an odometer-like instrument installed in most cockpits. Pilots record many details about their flight time, such as whether a flight occurred during the day or at night, in a single- or multi-engine aircraft, in visual or instrument conditions, and the pilot's role during the flight.[3]