This is the Traxxas 3000mAh 8.4V 7C Flat NiMH with iD Technology.

Features:
iD Technology
Engineered specifically to fit Traxxas models
12AWG multi strand wire is soldered directly to the LiPo cells eliminating increased resistance from bullet connectors and accidental reversed polarity connections
Semi rigid construction does not require a hard case and eliminates wire harness connectors that can loosen and fail
Requires:
LiPo charging bag
EZ-Peak Plus 4-amp NiMH/LiPo Fast Charger with iD™ Auto Battery Identification
Specs:
Length: 155mm (6.10")
Width: 44mm (1.7")
Height: 23mm (0.91")
Weight: 380g (13.4oz)
Charge Rate: 3A