IPS-Twin Power System Weight: 42 grams / 1.50 oz. Gear ratio: 84T / 12T = 7.0 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: 12 x 6, 12 x 8, 13 x 6 1/2, 13 x 9. Recommended Batteries: NiCAD 6.0V - 150ma GWS, NiCAD 7.2V - 350ma GWS, NiCAD 8.4V - 350ma GWS