Master airscrew props are real sharp. i found out just by taking it out the package. i also held the prop as i was tightening it and it cut through my hand like a knife through butter. i now alwys use a welders glove anytime i hold tprops when tightening them or even starting the engine. I only owned 1 plane that used rubber bands and hated it so much i changed it to bolts. we had a guy at our field that did not change the rubber bands as often as he should and the rubber became weak and brittle because of the fuel/oil. that wing looked so pretty floating down to the ground