FlightPower EVO 25 3700 2S (7.4v) 25A/50C (92.5A/185A)
High Discharge Lithium Battery
* Type: 3700 2S
* Voltage: 7.4v
* NiCad/NiMh equiv: 7-8 cells
* Continuous discharge: 25C (82.5A)
* Sustained discharge: 30C (111A)
* Max burst discharge: 50C (185A)
* Dimensions: 15 x 46 x 146mm
* Weight: 196g
* Cables: High quality silicone
* Balance plug type: Flightpower (Multiplex/Thunderpower)
see it
here
£25 posted
can't use LiPo in my club 
, something to do with safety
been used in T4, B4, TT01