This is the Great Planes ElectriFly RimFire .60 50-55-650 Brushless Outrunner Electric Motor. FEATURES: For Sport airplanes up to 10.5lbs (4705g) and 3D airplanes up to 6.5lbs (2950g) Designed for explosive acceleration and maximum torque Lightened aluminum can houses high torque rare earth Neodymium magnets Double shielded bearings Virtually maintenance-free; no commutators or brushes to wear out INCLUDES: Great Planes ElectriFly RimFire .60 50-55-650 Brushless Outrunner Electric Motor with prop adapter (GPMQ4909) and motor mount REQUIRES: Speed control for Brushless Motors such as the ElectriFly Silver Series 60 Propeller: 12x6 - 13x4E SPECS: Can Diameter: 1.97" (50mm) Can Length: 2.17" (55mm) Shaft Diameter: .32" (8mm) Shaft Length: .79" (20mm) RPM/V (kV Rating): 650 Weight: 10.5oz (298g) Input Voltage: 18.5-22.2V (5-6S LiPo) Connector: 4mm bullet plugs Burst Watts: 2200 Max. Constant Current: 65A Max. Surge Current: 85A Max. Constant Watts: 1683W No Load Current: 3A COMMENTS: The three number designation refers to Motor Diameter, Motor Length and kV Rating. jxs 4/20/06 ir/jxs