Maxamps 260mah 3.7v LiPo Battery Pack (2 batteries) for Traxxas QR1 and Husban X4 Quadcopters Perfect lipo upgrade for Traxxas QR-1 Quad-Rotor Helicopter. Get longer flight times, more power, and more cycles. 260mah capacity 1-cell 3.7 volts. 30mm X 19mm X 7mm, 8 grams 5C fast charge capable Short leads for lower resistance and a better fit Fits in the Traxxas QR1 and Husban X4 Polarity on this battery is specific to the Traxxas QR-1 and can NOT be used on the Heli-Max 1SQ.