This version surpasses all previous recorders with regard to its recording time of 50 days. This is only possible thanks to the used rechargeable Li-ion battery with 3.7V and 18Ah. It enables the PKI 2125 Digital Long-Term Recorder to operate completely independently of any connected power supply so that it can be placed and used universally and immediately. The playback quality leaves nothing to be desired, despite the transmission speed reduction to 32kbps. Moreover, battery packs with smaller dimensions can be delivered for 10 or 20 days.