TA only make their chainrings from the best 7075 T6 heat treated aluminium sheet. The teeth are cut in the traditional manner on a lathe which produces a much better and more accurate tooth form than pressing which is used by most chainring manufacturers.* Nerius for Campag 11x only, can convert Some Campag Carbon 10x chainsets to 11x. * Can be fitted to Super Record, Record, Chorus, Athena and Centaur chainsets. * Weights: 34T 29g to 50T 78g> For post 2011 11x Ultra-Torque chainsets please use TAD305 (threaded inner bolts) when changing the inner chainring.