This is one of the most economical batteries ever produced so stop spending money on batteries that just don’t go the distance! The USBCell provides powerful 1.5V performance and has a patented, built-in USB port, which you can conveniently recharge in most USB ports. The lithium technology provides constant maximum energy output and low drain for minimal self-discharge. One USBCell battery can be recharged up to 500 times and has a rapid recharge time of 2 hours, which is three times faster than traditional rechargeable batteries. There are four AA batteries in the pack.