Prologo nago evo x15 tirox mtb saddletirox rail light alloy steel highly resistant to traction and torsion for its physical characteristics and light weight is used in the aviation and aerospace industry t irox 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 active density it is the system patented by prologo that combines multiple base stiffnesses and multiple padding densities for a new level of co