1700mAh 2S 6.6V LiFe Battery with Futaba Connector from Futaba - FT21700B
This LiFe transmitter battery can be used in the following Futaba transmitters: 16\/18SZ, 14SG, 10J, 6K, 6J, 4PV, 4PX\/R, 4GRS, 4PKS\/SR and 4PL\/LS.