This Whip-O-Lite shade is No. 309-variegated from 1941. It was designed for use on Aladdin table, hanging, and bracket lamps.
I once owned this shade many years ago and traded it off. Years later as my interest grew I regretted having done so and I began hunting for one to replace it. It took years to acquire this one and at this time (April 8, 2019) I have only owned this one for a day!
I had to light this one up for you to show you why I regretted trading it off. Before I traded it, I displayed the shade in the display room of the Aladdin Knights at there national gathering in Omaha Nebraska the summer of 2000. I believe it was on a green moonstone Florentine vase lamp.