This is the E-Flite LiPo Battery 3000mAh 3S 11.1V 30C with EC3 Connector.
Specs:
Type: LiPo
Capacity: 3000mAh
Voltage: 11.1V
Connector Type: EC3
Wire Gauge: 12 AWG
Configuration: 3S
Maximum Continuous Discharge : 30C
Maximum Continuous Current : 90A