This very innovative acoustic guitar pickup system incorporates an L.R. Baggs Element undersaddle pickup element with the Mi-Si Simple Jack battery-free active preamp/endpin jack. The unique aspect of the preamp is that you power it up with the special Mi-Si charger, which connects to a standard AC outlet (120/220 V) straight to the output jack. Sixty seconds later (yes, just one minute) the preamp is fully charged for an effective playing time of 8 hours!