This is the Gens Ace Redline 2S LiHV 4000mAh 130C battery with 5mm Bullet Connectors. This high voltage battery offers increased power and runtime compared to traditional LiPo batteries giving you unmatched performance. Gens Ace batteries have been proven within the Radio Control community to deliver reliable and consistent performance for all modelers alike. All Gens Ace batteries offer superior cell matching at the factory, and are extremely consistent in selecting matched cells after each and every batch produced. Additionally, low internal resistance (IR), offers modelers stable voltage output through the whole duration of the battery.