This is a vintage cut corner rectangular wire frame for making a tailored soft bodied lampshade. 
Base 16 x 10 1/2”
Height 10 1/2”
Top diameter 8” x 5 1/2”
Duplex fitting (for use with shade carrier which isn’t included). I would suggest an 6” carrier.
Note that this is a vintage but unused frame. It does have some scuffs etc but no flaking or rusting.