Prologo zero ii pas t20 saddlea flat roadxc saddle for short to medium distance riding it uses a chromo t20 rail with a very high tensile strength this flat saddle is perfect for short to medium rides shape flat end use road learn more with the prologo buying guide features t20 rail the t20 rails are light high strength chromo rails pas this is a processing of the base where a channel has been created down the centre to eliminate pressure from the pelvic area ensures optimum comfo