Tenergy Combo: 5pcs of 3.7V 600mAh 25C LiPO Battery for UDI U818A/818A-1 2.4G 4CH RC Quad Copters Direct replacement battery for UDI U818A/U818A-1, no modification is needed t will give more PUNCH and ROBUST performance due to its higher current output and power. Battery Size (Max.): 57.0 x 18.5 x 7.8mm Retail package includes: 5 x Tenergy 3.7V 600mAh 25C LiPO rechargeable battery Capacity: 600mAh, Max. Discharge Current: 25C