This is a Traxxas 3S 11.1V 5000mAh 25C Short LiPo Battery Pack. Traxxas Certified iD-Equipped LiPo batteries are engineered to provide the punch and on-demand power for reaching the top speeds that Traxxas models are built to achieve. Traxxas Power Cell iD-Equipped LiPo batteries are engineered specifically to fit Traxxas models and maximize their full performance potential. Only Traxxas gives you more of what you want most: simple installation, a great price, and the most speed and run time available.