The aluminum trim around the front and the back cover are the only outer metal, and the Z hinge is all metal, rest is what I think they call soft touch plastic, feels quite durable so far, my only complaint about the industrial design is there is no switch to lock the hinge open or closed, and it can seem a little too easy to open/close as a result. I would have liked to see something like the lock for the battery door doubling as a lock for the keyboard, like you press it in reverse against a spring to release battery door and otherwise it locks the keyboard, but anyway. It does feel quite solid though and overall the build quality is what you'd expect from HTC, excellent.