Rode have taken a brilliant microphone in the Rode Videomic Pro and added a lithium battery. Of course there is more to the upgrade than that but this new battery achieves much longer run time over the 9v option of the Rode Videomic Pro, (upwards of 100 hours !!! ) with the ease of recharging the battery by Micro USB. If for some reason the inboard battery stops (like you forgot to charge it) you can use 2 x AA batteries to get you through the shoot.