AFAIK:
Fogger V4.0 non threaded without space in the afc ring for an oring
Fogger V4.1 non threaded with a little rim cutout in the afc ring
Fogger V4.2 threaded afc ring with copper 510 center pin
Probably the first batches were the first two versions "prototypes" that they sold off as they "perfected" the manufacturing process.
IMO the ideal AFC would be an air flow control ring with a shallow cutout in it that fits into a pin in the atty that lets the afc ring only move about 3-4 mm around the holes. Maybe in V4.3?
Fogger V4.0 non threaded without space in the afc ring for an oring
Fogger V4.1 non threaded with a little rim cutout in the afc ring
Fogger V4.2 threaded afc ring with copper 510 center pin
Probably the first batches were the first two versions "prototypes" that they sold off as they "perfected" the manufacturing process.
IMO the ideal AFC would be an air flow control ring with a shallow cutout in it that fits into a pin in the atty that lets the afc ring only move about 3-4 mm around the holes. Maybe in V4.3?