This is the E-Flite LiPo Battery 7.4V 1300mAh 2S 20C 18AWG with EC2 Connector.
Specs:
Type: LiPo
Capacity: 1300mAh
Voltage: 7.4V
Connector Type: EC2
Wire Gauge: 18 AWG
Weight: 2.40 oz (67.5 g)
Configuration: 2S
Length: 2.65 in (67.5mm)
Width: 1.40 in (35.5mm)
Height: 0.60 in (15.0mm)
Maximum Continuous Discharge : 20C
Maximum Continuous Current : 26A