Prologo nago evo x15 nack mtb saddlenack nano carbon fiber rail carbon fiber kevlar and aluminum filaments seat post clamp area treated with the production process called braided carbon rail bcr this is done in order to obtain the perfect fusion and uniformity of the different types of fibers and materials the result is a balance structure active density it is the system patented by prologo that combines multiple base stiffnesses and multiple padding densities for a new level of comfor