This is probably the kayfun Lite (V1), because has the airflow screw on side (i don't know if it is original or not!?) !
The kayfun Lite Plus 22mm 2014 Original (V2), it's almost the same (i don't know in dimensions, but probably they are !?), but it has the airflow screw on the bottom, different branding font on the bottom, new drip tip, on the top part of the top cap where the drip tip goes has slightly different angle cut ! Later on you could find many deferrent upper sections (chambers, chimneys, caps, bell-caps) from other moders that you could fit on the original base !
It's complicated. I've never had one with the air screw on the side.
There was a lot of confusion about the designations. I read once that V1 meant a single air hole, V2 meant two air holes. I have a mixture of one and two air hole tanks. But I got some that were sold as V2 but only had one air hole. The clones all called themselves V2. There were some differences inside as well. I ordered several of those Kayfil tools, only the one from C de V fitted my tanks, the ones FT sold were a slightly different diameter. Mine were mostly EhPro clones, I did get one that I think was an Infinite clone and the chimney was different, and a Tobecco that had an adjustable positive pin so it could be used on a mech. Even my EhPro clones had differences in the engravings on the base part. On some the lettering was in straight lines like yours which I think is how the genuine ones were, on some the lettering was curved to match the shape of the base. I got a couple from FT that came in boxes that were faked to look like genuine Svoe Mesto boxes.
Wish I had been able to pick up some of those aftermarket parts you mentioned. Maybe they are still available somewhere but I haven't seen them. If I see any I'll let you know.
Mine is probably not V2 (lite plus). As far as I could see, it had the AF screw on the bottom, while the one I have, most probably the V1, has a side AF umbrako screw.
3.1 probably doesn't have a filling screw from the bottom that V1 and V2 have.
V2 maybe had s/n, don't know if V1 had s/n, or when SvoeMesto started with s/n.
I don't know how careful the clones were in copying the engraving etc.
So for all I know it could be the original I have, or a clone.
I may have found the part I can use, will check with the store if they can use something other than DHL to ship.
Tank Metal - Kayfun 3.1/Lite/Lite Plus
Tank Metal - Kayfun 3.1/Lite/Lite Plus Tank Metal Kayfun en acier inoxydable pour votre atomiseur reconstructible de chez SvoëMesto. Ce tank vous permettra d'utiliser vos eliquides "agressifs" sans aucun probème.
