Made of stainless steel, but not high quality stainless steel. The hose is really cheap as are the hose clamps, and these will need to be changed. The steel plunger system appears very strong and durable and that is the heart of a sprayer. Having a pressure gauge is a nice touch. All in its about as good a sprayer as you can find anywhere and I looked at a lot of them, but as with every other sprayer out there it_ not perfect.When unpacking the sprayer has a horrible metallic smell, I had to put it outside my house it was that strong but it goes away after a few days