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

Great Planes ElectriFly RimFire .60 50-55-650 Brushless Outrunner
Electric Motor with prop adapter (GPMQ4909) and motor mount

Speed control for Brushless Motors such as the ElectriFly Silver
Series 60
Propeller: 12x6 - 13x4E

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

The three number designation refers to Motor Diameter, Motor Length
and kV Rating.