The speed of a mechanical pendulum clock is not constant, fluctuating with age and wear, spring tension and even temperature. The ClockMaster app was created with a focus on accurate long-term measurements where traditional timers often do not function very well. For the professional horologist or interested amateur, you can now test in the field — put the clock in exact beat and regulate the clock with just a few hours of testing. For increased rate accuracy and in depth investigation of clock movement's behavior, you can conduct long-term measurements for up to two weeks (ClockMaster Pro). Branded, printable PDF reports can be generated for each measurement, and the raw data exported as .csv file for graphing in a spreadsheet (ClockMaster Pro). ClockMaster Pro (in-app upgrade) provides these additional features: • Save and share branded, printable PDF reports for each measurement • Export raw measurement data as a .csv file for spreadsheet analysis • Conduct long-term measurements of up to two weeks