This is the Great Planes ElectriFly 20mm Ammo Gear Drive. The motor attaches to the mount and the prop attaches to the gear drive.
For 20mm Ammo Motors and most other 20mm In-runner motors High-precision spur and pinion gear for quiet operation. Dual ball bearing-supported output shaft. Standard 10x10mm stick mounting system.
Length : 1.84 in. (46.7mm)
Width : 1.66" (41mm)
Weight : 0.42oz (12g)
Motor output shaft dimension : 2mm
Prop adapter shaft dimension : 3mm
Gear ratios included :
5.3:1 and 6.4:1
5.3:1 with 12T pinion and 64T spur
6.4:1 with 10T pinion and 64T spur