1S1200JST : 3.7volt 1200mAh Li-POLY 1S rechargeable Battery (20C) for Helis, Planes, Quads.  Has red JST connector for direct hookup to motor or speed controller.  Plugs right into model.  Re-charges quickly; can be used over & over!
Upgraded specifications.  Size: 2" x 1.2" x 0.38".  Part # 1S1200JST.

Recommended charger: 1S-CHG-JST (plugs into USB2.0)