This is an accessory set for the GPS tracker Trackimo, including a dedicated magnetic case and a 3,500mAh power pack. The power pack is rechargeable and can be used repeatedly. The standard battery capacity included is 600mAh, but the power pack battery has a large capacity of 3,500mAh, which is more than five times the capacity of the included battery. Using the power pack battery allows for longer operation. *The tracker unit is required for charging, but the unit is sold separately. (The unit in the photo is for charging and usage illustration purposes.) I used it for a short time, but my purpose has been fulfilled, so would anyone like to use it? I think the condition is good.