Tenergy Saving Combo: 2 Packs 25C 2200mAh 11.1V 3S Li-Polymer battery w/ EC3 Connector for 3D flyer of Trex 400/450 and other similar size RC Helicopters The best choose for 3D flyer of Trex 400/450 and other similar size helicopters. Continuous Discharge Rate: 25C / 55A Burst Discharge Rate: 30C / 66A Dimension: 108x 34x 22.5mm 25C high discharge rate will give you the power you can never think of. Long lasting and powerful.