Having a 22 quart Mirror pressure cooker, it was made in 1978. The gasket that with the pot was the original. I needed to can some deer meat and replace the seal this year. This fit very well, and once oiled with veggie oil and worked for 10 minutes, it fit very well. It looks to of the same design but a different material, which, since 1978, I am sure the material has been improved. I tucked the gasket into the rim and let it set for a couple days to normalize. Once it did, I found it to fit perfectly and when the lid was fastened, it was a near perfect match.