MaxAmps LiPo 400mah 1-cell 3.7v for 1si/1si Camera, 1sq/1sq vcam Perfect lipo upgrade for Heli-Max 1si, 1si w/camera, 1SQ and 1SQ V-Cam Quadcopter. Get longer flight times, more power, and more cycles. 400mah capacity 1-cell 3.7 volts 42mm X 19mm X 7mm 11 grams, 5C fast charge capable, Guaranteed Fit. Built with factory fresh cells when you order. Note: Polarity on this battery is specific to the Heli-Max 1SQ/1SQ V-Cam and can NOT be used on the Traxxas QR-1. V-Cam users: We have found that this battery will fit better if you loosen the 4 camera mount screws two revolutions.