IPS-Twin Power System Weight: 42 grams / 1.50 oz. Gear ratio: 58T / 14T = 4.1 Recommended battery is 4.8V (2/3 AA 270 to 600 mAh). Using higher than 4.8 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: 8 x 6, 9 x 4.7, 9 x 7 Recommended Batteries: 2 or 3 NiMH-AAA 1.2V - 600mAh NiCAD 4.8V - 110ma NiCAD 4.8V - 150ma