This is a transmitter only rechargeable battery pack that fits some Futaba transmitters and also other radio brands.

Fits Futaba Transmitters:
T4PM
T4PLS
T4GRS
T4PV
T4PX
T6K
T7PX
T7XC (tight fit)
T8J
T10J
T12K
T14SG
T16SZ
T18SZ
FX20
FX36

Specs:
For: Transmitters Only!
Battery Type: 2s Lithium Ferrite - LiFePO4
Voltage: Nominal 6.6V
Energy: 12Wh
Capacity: 1800 mAh
Length: 83.2 mm
Width: 39 mm
Height/Thickness: 14.75 mm
Weight: 85 g
Wires: 22AWG / 100mm
Connector: Futaba
Balance Connector: XH
Charging: 1.8A

Tech Notes:
Charge the battery outside the transmitter with a LiFe balance charger equipped with an Futaba adapter lead and XH balancing connector
Set the charger to ”LiFe”, 2s, 3.3v/cell