Luftschraube GWS 10x8 HDVery easy Indoor and Slowfly air screws.
HD=Hyper-Drive means strengthened blade base for a higher rotation speed
Attention: the mounting is intended for a hexagonal bolt (GWS gear) or a propsaver. For other carriers you need to drill the air screw (do not forget the balancing). The 2" types have got a bore hole of approx. 0,5 mm the 4" and 6" types approx. 4 mm.