Prologo nago evo tirox saddlethe nago evo tirox saddle has been developed specifically for riders looking for extreme lightweight but with maximum comfort in a semi round saddle shape semi round end use road learn more with the prologo buying guide featurestirox rail rail light alloy steel this material is highly resistant to traction and torsion for its light weight its for these reasons it is used in used in the aviation and aerospace industry tirox then turns out to be a rail with a