Vibrations per hour

Vibrations per hour or beats per hour is a mechanical timepiece specification. It is used to express the frequency of a watch movement.
VPH describes the number of times that a vibrating timekeeping component completes half a vibration cycle every hour.
In contrast, when measuring the same frequency in Hertz, it describes the number of times that the component completes a whole vibration cycle in a second. The frequency in Hertz can therefore be multiplied by 7,200 to determine the frequency in VPH.
A higher frequency is a higher timekeeping resolution, and usually indicates a higher precision mechanical movement. This allows a faster recovery from being knocked or bumped, with the tradeoff being a faster accumulation of wear and tear.