IPS-Twin Power System Weight: 42 grams / 1.50 oz. Gear ratio: 107T / 10T = 10.7 Recommended battery is 7.2V (2/3 AA 270 to 600 mAh). Using higher than 7.2 Volts will greatly decrease the lifetime of each motor. Using two heat sinks will extend both motor lifetimes. CAUTION: Using a larger than recommended propeller and/or higher voltage battery may cause permanent damage to this motor. Recommended Propellers: 14 x 10, 15 x 7.5, 15 x 10. Recommended Batteries:NiCAD 6.0V - 150mah, GWS NiCAD 7.2V - 350mah GWS, NiCAD 8.4V - 350ma GWS