I have fitted this HAYA 1/16 Centurion Barrel Fume Extractor "A" Type to my HAYA RTR Centurion and it fits the barrel perfectly and it grips tightly enough not to turn or move out of position, so it is important to position it correctly before adding any glue as it is not easy to rotate it once it is fitted. The two halves of the moulding clip together so well that they may not need any glue at all, but I prised mine apart and added some super glue to make it a permanent fit. Excellent quality and very good value for money. Top marks!