Cooper is a cast iron base with a steel column and spun steel housing that can be finished in a variety of colors.  Typically Cooper is furnished with a larger spider than shown in the photograph.

base dimensions

Cooper 17
A 17 dia
B 28
weight 38 lbs

Cooper 22
A 22 dia
B 28
weight 42 lbs

Cooper 30
A 30 dia
B 28
weight 74 lbs

Cooper BH*
*not recommended for 17" bases