Prologo nago evo pas tirox saddlethe nago evo pas saddle with tirox rails is a really technical saddle with a semi round profile its suitable for medium to long riding, and is backup with the great support from light pu padding and tirox rails.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 it's for these reasons it is used in used in the aviation and aerospace industry. Tirox then turns out to be a rail with a good balance between weight and strength, that doesn't fear the normal stress that addresses a bicycle.size mm 275x134 275x141weight gr 217 219base carbonfiber injectionrail tiroxcover microfiberpadding light pubuy prologo components from chain reaction cycles, the world's largest online bike store.