This is a vintage cut corner square wire frame for making a tailored soft bodied lampshade. 
Base 19 1/2” diameter (side to side)
Height 13 3/4”
Top diameter 9”
Duplex fitting (for use with shade carrier which isn’t included). Pictured on an 8” carrier.
Note that this is a vintage but unused frame. It does have some scuffs etc but no flaking or rusting.