GM-1 Group Metronome - 4 PackShare the same tempo, enhance your sense of rhythm, and move in time. The GM 1 is an ultra compact metronome that you can place on one ear in the same way as with earphones. Use multiple GM 1 devices and everyone listens so they can practice with the same tempo in sync. Metronome that syncs tempo across multiple devices 8 rhythm variations and 10 beats Three sizes of earpieces (S, M and L) included Low power consumption for approximately 100 hours of