This is the bakelite Euro, or Nord Socket with its thread-on retainer for shades built with a 40mm wire hole in the shade (pictured below). They are not compatible with the UNO, threaded ring shades. They are very strong and won't loosen up, as the UNO system does, often resulting in bare wires and flopping shades. The shades I supply for these sockets are natural linen fabric, made for me by the Brunswick Shade Co of New Jersey. I have them in 9 and 12 inch bottom diameters, shown below.

This is not the style I use on the floor lamps.

To find instructions on how to wire a standard washer-top shade onto one of my lamps, CLICK HERE.

Twelve-inch Linen shade, 40mm Nord ring, fabric binding top and bottom, plastic liner,

$15

The manufacturer does not recommend it, but I have washed fingerprints and dust off my craft fair display shades using a soft brush, mild, dilute detergent and a brief under-the-kitchen fawcett rinse, followed by re-installation and illumination for a quick dry.

Nine-Inch linen shade, as above.

$13