Three Rare features : Factory Marked, Frosted Band, and Tall Size.
Factory marked Standing Glass Blower Logo "Keystone Glass, Best Lead" at top of flue with the Rare "Frosted Band" which was Hand Tooled while the glass was still Hot !
12 inch Tall # 1 size Chimney with the standard 2 1/2 inch base slip fitter .
Great for a smaller Hanging Lamp with a Rare # 1 collar & # 1 Burner !
Could also be used inside smaller GWTW Lamps with # 1 burners.
Possibly Experimental, I believe the Frosted Band was done as an option to prevent Glare from the flame when the hanging lamp is above the Table and your trying to see your other seated guests across the hanging lamp above that same table.
Top and Bottom were both Fire Finished Smooth.
Profile is Complete with one micro chip at the top of the flue which was rough cut and fire finished afterward. See Close-Up photos.