This is the Great Planes ElectriFly Ammo 28-35-3900kV Brushless In-Runner Electric Motor. FEATURES: Brushless, slotless Ammo In-Runner Motors offer an incredible power- to-weight advantage and almost twice the efficiency of Brushed motors Ideal for direct or gear drive use Up to 89% efficient and virtually maintenance-free; no brushes to wear out Powered by "rare earth" Neodymium magnets for high torque and unmatched heat resistance Pre-installed gold plated connectors for plug and play operation when used with compatible ElectriFly Silver Series Brushless speed controls Double sealed bearings Two year warranty INCLUDES: Great Planes ElectriFly Ammo 28-35-3900kV Brushless Electric Motor with connectors and four M3x5 machine screws REQUIRES: Installing in model and connecting to speed control Propeller, suggested sizes are 10x7E-14x7E SPECS: Motor Diameter: 1.1" (28mm) Motor Length: 1.378" (35mm) Shaft Diameter: .126" (3.2mm) Shaft Length: .591" (15mm) kV Rating: 3900 rpm/V Weight: 3.3oz (94g) Input Voltage: 7.4-11.1V Max. Constant Current: 22A Max. Surge Current: 45A Max. Constant Watts: 244W No Load Current: 1.8A jxs 2/23/06 ir/jxs