The ultimate racing battery cells, 1.23v BRCA Legal
The 1.23v is not zapped so will not drop in voltage if not used ! 

Dimensions: (Max) 41.8mm long x 22.2mm diameter
Weight: 65g
Capacity: 4300mAh - Measured at 30A Discharge!
Average discharge Voltage (MPV): =>1.23V
Max Discharge Current: 35A Continuous, 65A Bursts are possible.
Max Charge Current: 6000mA

Source : Vapextech UK