Anyone know what stove these are for? They came in a box of burner bits. They look like they are off a small petrol stove (8R, 123R, 71, 80 etc). The collar is formed and threaded on the inside of the bell as shown. I thought they may be off a late 8R model with no tank clip as shown here, but mine have two small holes rather than the four shown in the link. Any help with the ID would be appreciated.