This is the Great Planes ElectriFly Ammo 28-45-3600kV 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 28-45-3600kV Brushless Electric Motor with connectors and four M3x5 machine screws

Requirements

• Installing in model and connecting to speed control
• Propeller,suggested sizes are 9x6E-15x10E

Specifications:

• Motor Diameter: 1.1" (28mm)

• Motor Length: 1.77" (45mm)

• Shaft Diameter: .126" (3.2mm)

• Shaft Length: .591" (15mm)

• kV Rating: 3600 rpm/V

• Weight: 4.6oz (133g)

• Input Voltage: 7.4-14.8V

• Max. Constant Current: 40A

• Max. Surge Current: 70A

• Max. Constant Watts: 592W

• No Load Current: 2.3A