A Garmin fēnix serves as my personal 'on-board' bio-interface. It's sensor array yields the physiological metrics, telemetry and local environmental data required to fuzzily estimate net pace and predict finish time during a run.
However, I also like to 'preflight' speed, distance and time more accurately when aiming for a PR, particularly when running a familiar route. This simple static chart allows me to do just that.
Cheetah icon created by M. Turan Ercan from the Noun Project.