This is a quality wire frame in 6 sided shape for making a pleated/gathered  or tailored soft bodied lampshade.
Base diameter 10 1/2”
Slope height 8 1/4”
Top diameter 5 1/4”
It hazard wire at the base to allow the bias trim or braid to sit neatly.
It  an EU fitting with a reducer washer for standard UK BC bulb holders
This is a vintage but unused frame please note there are a couple of scuffs here and there.