Stainless barrel and cylinder. I bought one a few years ago as a "replacement" () for an M49 that I stupidly sold many moons ago.

They take a bit of break-in and a lot practice, and come awfully dry and stiff from Mama Smith. A little lovin' and lubin' is required. Shoot a mess of target wadcutters before stepping up to defense loads. You will be happy that you did if you are not accustomed to Airweight J-frames. Once you become used to them they become addictive.