Tenergy 2 Pcs RCR123A 3.0V 400mAh LIFePO4 Rechargeable Batteries with a Smart Charger (Not for Arlo Camera) BATTERIES NOT COMPATIBLE WITH NETGEAR ARLO SECURITY CAMERAS. (For Arlo compatible batteries, go here: http://www.amazon.com/dp/B01MRKGS4K) PLEASE ALSO DO NOT USE WITH SUREFIRE FLASHLIGHTS OR E-CIGS. Can charge 1 or 2 RCR123A from 2.5 hours to 5 hours. Peak voltage of 3.2V LiFePO4 will be 3.6V after fully charged. Smart, build-in microprocessor automatically switch off when batteries are fully charged. Safe, build-in IC provides various protection, thermal protection, overcharge protection, short-circuit protection, mechanical and electrical protection against reversal polarity, and auto defective battery identification. Compact ( 2.5 x 4 x 1 inch ), Light weight ( 5 oz only ), include charger and all accessories. Convenient, 12V car cigarette lighter plug for on the road charging. Buy with confidence, your charger includes a 12-month warranty.