High Power Capacity: Includes Tenavolts AA High-Capacity Rechargeable Batteries pre-charged, each with 2775 mWh. Great use for high-power demand device, including insulin pump, toys, remote controls, and portable audio players. 1.8 Hours to Fully Charged: Get a full charge in 1.8 hours. Much faster than traditional Ni-MH rechargeable batteries which need 3 hours to fully charged.Constant voltage and Best Performance: Tenavolts rechargeable lithium batteries are far superior in voltage retention. Designed with innovative technology, Tenavolts outputs 1.5 voltage from 100% to 0% electric capacity, providing constant voltage and best performance in heavy load discharge.Long-lasting batteries, Less Waste: Tenavolts can be recharged in 1,000 cycles. Since discarded batteries are terrible for the environment, from environment perspective, rechargeable batteries are more economical and better than regular batteries for the environment.Unique recharge design: Tenavolts AA batteries can only be recharged with the authorized unique Tenavolts battery charger. The Tenavolts battery charger satisfies the special recharging requirements