This is a quality, one-of-a-kind lampshade frame for making a statement ceiling pendant. It also has supports for a diffuser.
Note that this is a vintage, but unused frame, it does have scuffs and scrapes et cetera
Base diameter 23”
Vertical height 11” to bulb holder 
Top diameter 4 3/4”
EU ring fitting with washer (not shown but I will include it) to reduce to UK standard BC fitting.