These Spektrum Prop Saver O-Rings, 5pcs are compatible with the E-flite Park 250 Brushless Outrunner Motor (EFLM1130), E-flite Park 300 Brushless Motor (EFLM1150) and the Great Planes Rimefire 150 14-05-3000 Outrunner Brushless (GPMG4453).