DarwinFPV 1104 4300Kv is an affordable motor for 2-3" propellers combined with a 3-4S battery. The motor has a 1.5mm shaft that the propeller presses on. The propeller is not secured with screws. The motor mounting holes are 8.5mm M1.4 . The motors were originally made for the DOBBY pocket drone. However, the company that manufactured the drone has gone out of business and DarwinFPV is now re-selling the motors at a discounted price.