This very innovative acoustic guitar pickup system incorporates a 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. 60-seconds later (yes, just 1-minute) the preamp is fully charged for an effective playing time of 8 hours!! No more batteries. This system works on most straight saddle acoustic guitars, or any acoustic string instrument with a removable saddle. In fact, this is an excellent pickup system for ukulele, because the preamp does not take up a lot of space inside the uke body. Professional installation highly recommended. Charger is included.