Yes, that's exactly what that was for. In the early-mid 1990's, there was an organization called Sport Fliers' Association that was trying to compete with AMA. Per their safety code, you had to use one of these to adjust the needle. This was before the days of the remote needle being the norm. Needless to say, most thought this was more dangerous than getting their fingers near the prop. Both it and the Sport Fliers' Association are long gone.