This is a vintage curved corner square wire frame for making a tailored soft bodied lampshade. 
Base 20” diameter (side to side)
Height 15”
Top diameter 10 1/2”
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.