Flat rubber washer sizes and source (for small number)?

[pasadena_commut]

There is a diverter on our bathroom Moen faucet which looks more or less like this one:

https://i.ebayimg.com/images/g/vF0AAOSwiPxgVDHF/s-l1600.png
except there is an adapter between it and the spigot. There are two flat rubber washers which are both pretty shot (stiff, not sealing well), "A" between the adapter and the faucet, and "B" on the aerator. They both came with the no name diverter many years ago. Their dimensions are, as best I could measure (using the the same ruler twice, first in mm, then in inches):

A
OD 21 mm, 13/16"
ID 15 mm, 9/16"
Thickness 2.5 mm, 3/32"

B
OD 20 mm, 3/4"
ID 11 mm, 1/2"
Thickness 2 mm, 1/16"

My son had to visit an Ace hardware for something else and looked for these, but came up empty. He could match one dimension, but not both ID and OD at the same time, and most of the packs didn't even specify thickness.

Anybody know a place on line with a big assortment which will sell one washer of a specific sizes? That is, I don't need a pack of even 5, just one of each.

Also, is either of these a standard size? B might be 1/2R but the center hole seems to be a slightly different size.

 

[Twowaxhack]

You need an aerator washer for one side Buy an aerator and rob the washer out of it.

And you’ll need one of these
https://www.homedepot.com/p/Glacier-Bay-1-2-in-Showerhead-Washers-3-Pack-3075-561/204511132

 

[pasadena_commut]

That was helpful - I had not thought about it, but both of those washers were in a sense "aerator washers". The top one was for the original Moen aerator. Searched for "aerator washer" and found this:

https://www.acehardware.com/departments/plumbing/faucet-and-faucet-repair/plumbing-washers/4205266
which is very close in OD and ID to "A", probably within my measurement error. The one you suggest should work on the other end.

 

[pasadena_commut]

Fixed now, but it was peculiar. The Glacier Bay washers turned out to be too thick to use on the aerator, not enough thread could engage to screw it on solidly. Also for some obscure reason the Danco washer leaked at the diverter/faucet junction even though it seemed to be almost exactly the same size as the original. So each was used in the other's intended position, which worked without leaks.