I was mistaken regarding the ball head material. I was handling the tripod in a warm room and the materials did indeed feel like a high-density resin. This evening I came home to a cold house and touched the head. Surprise! There was the unmistakable feel of cold metal. I made a few discrete scratches and took off the plug from the bottom of the hollow ball and am able to confirm that the construction of both the head body and ball is metal--probably magnesium, though I am not going to hold it up to a flame to confirm.
I have edited the review to reflect this recent information.
Steve
(Much higher opinion of the head)