Amazon.com : Eyeline Golf Metronome Tour Edition - Tempo Trainer Pro Audible + visual Pacing Device, Portable on cap or ground. Beep or flashing light. Adjust for putting, chipping, full swing. Indoors/outdoors. :
Metronome (Click) 600 BPM - YouTube
Metronome goes from 60 to 600 BPM in less than a minute. Warning! This can be stressful - YouTube