The Firefly 2, as all users of them know, comes with a spare battery which is a huge bonus but if you are the kind of person who kills the batteries faster than you can charge them up then you know how frustrating it is when you have to choose between using your fully charged battery or using the dead battery and charging it while you use it. Finally you don't have to worry about making that choice with this external charging bay for the Firefly's batteries. You simply slide your empty battery into the charging bay and plug the charger into your existing Firefly charging lead and you are off and running. You can now charge one battery while the other is being used and get much more efficient use out of your device. You don't have to worry about waiting around for ages either, this charger takes the standard Firefly batteries from empty to full in as little as 45 minutes. With LED's to let you know your batteries status it has never been easier to keep your Firefly running 100% of the time.