The larger threads are not 510, that much I know. 510 threads are female so that a male threaded carto can fit on them.
Again anything 808 will fit on the Vapor4Life ego, whether it be a cool cart, wow, mega, tank, clearo, etc. 901 atty's will fit on the Vapor4Life ego as well. The 510 stuff won't, it's a female connection instead of a male. The 510 ego stuff still uses a 510 connection, the outside threads are for extra grounding and securing of the large ego tank cartos and atty's...
ROFL!!! I didn't even notice that!
Luckily I did catch my phone when it wanted to type WTF instead of WTG!!
I had been wondering the same thing about the sleeves. So when I learned that such things existed so my tank wouldn't look all funny, I was overjoyed.. However the large threads on the 808 ego, are smaller in diameter than the larger threads on the 510 one, believe it or not.. (I am now the proud owner of 3 sleeves that will only work with 510 ego's)