This is the New HQProp POPO Quick Swap compatible !
It also can be used for NON POPO motors.
2x 5.1X3.1X3 CW propellers
2x 5.1X3.1X3 CCW propellers
Mounting hole: 5mm
Center Hub Thickness: 7mm
POPO Compatible: Yes (You can still use them with regular motors)