Racers Edge 25C 5000 mAh 2S1P LI-Poly Battery with Deans Ultra Plug. Racers Edge battery is lighter than traditional Ni-Cd or Ni-Mh batteries while offering improved performance and run times. It uses the same balancing connection as Align or Electrifly chargers. Be sure to use a voltage cut off if yRacers-Edge speed control doesn't come equipped with one. ONLY USE A CHARGER SPECIFICALLY FOR Li-Poly cells!!! Due to recent updates in shipping regulations for lithium batteries, this product will not ship using USPS.