Already have the fin holder you need for your new rocket but it's a different diameter? Just order the rings! Diameters are as follows:
2.2"CB - 57.4mm
2.6"CB - 67.35mm
3"FG - 79.3mm
3"CB - 78.6mm
4"FG - 102mm
4"CB - 101.5mm
4.5"FG - 114.5mm
5"FG - 130.6mm
5.5"FG - 140.34mm
5.5"CB - 140.5mm
6"FG - 156.72mm *DOES DOES NOT INCLUDE FIN HOLD
