Rechargeable battery, just fit the base of any Nuki lock model. It has a USB-C plug on each side, to allow charging with the pack assembled. Autonomy is about twice that of normal batteries, lasts for about 6 months (8 movements/day), and notifies you on the App when it is at 20% charge. The charge level can be consulted on the App.
Barcode: 554061224821 | 9120072081354