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 your speed control doesn't come equipped with one. ONLY USE A CHARGER SPECIFICALLY FOR Li-Poly cells! Like all Racers Edge batteries and chargers, this pack is guaranteed to be free of factory defects for one year from purchase. 1 YEAR WARRANTY!