The listing is for a 8" washer ring (also know as a Spider) with a 1/2" drop. No bottom ring is included with this listing 11g - Galvanized. Silver Color. The inner-dimension of the washer fitter is 1/2".
If your lamp has a harp, then you will need a washer fitter.
I expected to get both top and bottom like in the picture and title, got the top only. Didn’t think to look at description since it was obviously listed that way.