Rechargeable 18650 Li-ion battery with Protection Board(flat poles) , so-called Flat top.The function of the protection board is to protect the battery from being over-discharged, over-charged, over-current, and output short-circuit protection.The function of the protection board is to protect the charging and discharging of lithium batteries in series; it effectively improves the charging effect in the series charging mode, and at the same time detects the overvoltage, undervoltage, overcurrent, short circuit and overtemperature of each single battery in the battery pack status, protect and extend battery life.The batteries are pre-charged and ready to useHigh discharge performanceLong cycle life, more than 500 timesNo memory effectFits in e.g. flashlights, headlamps, laptop, toys,video camera, robot , alarm accessories and so on. Not suitable for e-cigarettes and other devices with extra large power requirements.SpecificationName: Laddningsbart Li-ion 18650 Battery with Protection Board(Flat top)qty: 1pc/packageVoltage: 3.7VmAh : 2600mAhSize: 18x65mmWeight: 50g