RX4s you'd need hope fittings to go with but they are included, whatever shimano you go for will work, you'll probably get away with just unscrewing it and screwing the new one in but wouldn't hurt to have the correct olive and barb for your hose to hand just in case.
RX4s you'd need hope fittings to go with but they are included, whatever shimano you go for will work, you'll probably get away with just unscrewing it and screwing the new one in but wouldn't hurt to have the correct olive and barb for your hose to hand just in case.