The model number is 7A.
Hmmm, when I check Presto sources, the following comes up:
The following models have been discontinued by Presto:
606-6 Quart Pressure Cooker
60 (6-quart)
412-4 Quart Pressure Cooker
402-4 Quart Pressure Cooker
400-6 Quart Pressure Cooker
304-4 Quart Pressure Cooker
14-Size 21 Canner
100-6 Quart Pressure Cooker
7A-Size 21 Canner
5-Size 12 Canner
But when I checked some other sources for sealing ring, I found some that have Presto #09907 which the box says:
* With air vent
* Fits Presto 16 and 21 qt. canners
* Mfg. Nos. 7, 7A, 7AV, 7B, 7S, 14, 21, 21AV, 21B, 21S, CA16, CA16H, CA21 and CA21H
That is from the Ace Hardware page:
http://www.acehardware.com/product/index.jsp?productId=1276408
I would be tempted to take it with me to see if the ‘Helpful Hardware Man’ couldn’t open one and see if it fits.
Hope this helps.
Oooops - maybe the description differs from the box - I looked at the enlarged box image and it does NOT have the 7A.
This is the problem I had last year about this time when I needed parts for my old Best Maid canner. That was why I got the All American so I wouldn’t have that problem as they don’t use seals - it is metal to metal.
Good Luck...