1.0 milliseconds -- cycle time for frequency 1 kHz
1 ms -- duration of light for typical photo flash strobe
2.27 ms -- cycle time for the A above middle C in music (440 Hz). If an electric tuning device for musical instruments generates just one tone, this is probably that tone.
... until one finds the "rolling" point, but the gyro will also be accelerated to a smaller extent by the slipping friction.
The device is covered by US patents ...