This prop aver is specifically designed for GWS style props which have a 4mm bore. It is made from hard plastic with a 0.95mm bore hole. It will fit motor and geardrive shafts with a diameter of 0.95mm to 1.0mm.

The prop saver can be used as is but depending on the diameter of the prop hub you are using, you may also need to file some grooves in the back of the prop saver to locate the o-ring securely. Please see images above for examples.