I strongly agree with Mont, all push n twist do not work well with all plugs. I have a Hanger 9 Mighty Midget (push n twist) and it can not and will not stay on a OS type F. The times I have used on it there, it would get stuck and I would have to be fighting it while a 14x6 prop is flying by hand. I've since purchased a dubro that has that spring loaded locking mechanism.

Good luck.