These caps all have a 5 1/4" (for 5" models) or 6" (for 6" models) inside diameter clearance that slips over the lips on top of the 5" and 6" rings that the larger Tiffany shades are equipped with.
C6PT
6" Pigtail Cap
Spun and etched brass
6 1/2" OD, 8 1/2" high
C5PT
5" Pigtail Cap
Spun and etched brass
5 1/2" OD, 7 1/2" high
C5TD
5" Teardrop Cap
Spun and etched brass
5 1/2" OD, 3" high
C5F
5" Favrile Ball Cap
Spun and etched brass
with iridized glass ball
5 1/2" OD, 3 1/2" high
C6TD
6" Teardrop Cap
Spun and etched brass
6 1/4" OD, 3 1/2" high
C5V
5" Volcano Cap
Spun and etched brass
5 3/4" OD, 2" high