Some confusion in this reply. The valves on both instruments are Nickel Plated brass. Basically the manufacturing process is to take a brass tube for the outside of the piston, then drill it for the port elbows. The elbows (also from brass) are pushed through and braised to the outer tube. After cleanup the entire assembly is Nickel Plated. This plates the elbows as well as the piston. Getzen valves are so good because they take a lot more trouble with them (plating thickness, fit etc) than Yamaha ever did with the 232, 2320, 2335 etc. In fact an achilles heel of these particular Yamaha models is the plating lifting from the valve. A Monel valve is a Monel tube fitted with Brass elbows. This is why Monel valves have brass colored elbows. Stainless Steel valves are made in the same fashion as Monel (Stainless Steel tube with Brass elbows). It is often difficult to discriminate visually between Monel and Stainless Steel. Hope this helps.