A pair (2) of 9V DC batteries with recharger. Indicator lights will let you know when batteries are fully charged. Batteries will not be overcharged by the plug-in wall recharger. There is no "memory effect" with these new lithium-ion batteries, and they have a very slow self-discharge rate being able to maintain up to 75% of its power after 3 years of non-use (of course, the batteries can be recharged at any time to power them back up to 100%). Can be recharged over a thousand times for a very cost-effective use of portable electronics.