This is a JR Extra 1400mAh 6V Receiver Battery Pack.  Built from premium quality SanyoŽ E-series cells, JR Extra Batteries have extended capacity and a linear discharge curve for easy charge monitoring. In fact, depending on your selection of packs, you can expect a 30% increase in flight time, or reduced size and weight over the standard pack that came with your system. They're quadruple-welded rather than soldered, and utilize extra-heavy-gauge wire for durability and low resistance. With gold plated connectors and double-thickness heat shrink, there were absolutely no compromises made in the construction of these hand-assembled battery packs.