This is a Traxxas Traxxas “Series 1” 6 Cell Pack. Traxxas sets the standard for engine-starting ease and convenience with its innovative EZ-Start system. By simply pressing a button, the EZ-Start unit lights the engine’s glow plug and powers the on-board starter motor for fast, fool-proof ignition. For best EZ-Start performance at a highly economical price, Traxxas offers the Power Cell 6-cell 1500mAh NiMH battery pack for EZ-Start. Featuring quality construction with rugged NiMH cells, silicone-jacketed 14-gauge wire, welded tabs, and a standard Molex connector, the Power Cell EZ-Start pack installs easily in the starter unit and provides plenty of capacity for all day starting power on a single charge.