A pair of good quality, Soshine 16340 button top batteries.
2x Soshine CR123 Rechargeable Batteries 3V 550mAh 3.2V LiFePO4 + Storage Case
Soshine Battery Charger - CR2 CR123 14250 2/3AA 14300 14335 16340 17335 15266
16340 CR123A CR123 3.7V 2550mWh Rechargeable Li-ion Battery USB Charger For Arlo
16340 CR123A CR123 3.7V 2800mAh Rechargeable Li-ion Battery / Charger LOT
16340 CR123A CR123 3.7V 2800mAh Rechargeable Li-ion Battery / Charger For Arlo
16340 CR123/CR2 Lithium Battery Dual Charger Battery Charger USB Charger