If I'm not mistaken, st- is slim and stainless steel& bb is ball bearings.. The v2 button is what we've all decided/voted the Lord and kiss should have.. brass accent, no slimmed lock ring, and it has the ball bearings.
Their top caps come with a 12 Amp fuse installed, and extras, like 6&8 Amp.. they are not a proprietary fuse to Gus.. But you'll have to have someone else tell you what they are called.. To my knowledge, all top caps come with various connectors for the top cap and estia in hybrid..but you can also replace the fuse pin with a nemesis, gg, and several other 510 screws...but to use the telescope in 18350, you have to use the two, rather large, brass contacts. I don't know if that is the case with normal 18350 tubes.