Pressed brass or also found in cast brass upper cap threaded on to a steel wheel locking ring on the bottom. The cap has an outside diameter of about 3 3/16" for the uper brass piece and 3 7/16" on the lower steel part. It is about 3 7/16" high and the thread opening is about 2 3/4". It is 2 1/2" across the flats.
