Du-Bro plastic spinners are fine to use on any sport type engine. They are high quality and will not shatter (explode) unless they are compromised, as in a crash, or extreme cold. I would avoid using them on high RPM engines like those used on speed A/C, or during winter in areas that have very low temps. In 30 years of flying the only spinners I have ever seen fail are the cheap cones that come on ARF's and that was after excessive abuse.