You can use whichever you like with the appropriate tank. Type A atomizer takes Type A
tanks and B takes B tanks.
The difference:
Type A is cone-shaped and accepts slightly less
juice than type B.
Type B is cylinder shaped (like the ones you have).
Type B is considered an "upgrade" to type A though many users still prefer the type A.
My personal experience:
Type B delivered a lot more vapor and throat-hit compared to Type A.
The EGO-T type B would've been great if those damn atomizers didn't die so quickly and weren't so expensive.
If you like tanks, try the new Vision EGO Stardust Clearomizer. They're a lot more cost effective and convenient than EGO-T (A/B doesn't matter)
You already have 2 EGO batteries. Instead of ordering more EGO T atomizers just order some Stardusts. You'll thank me for this later.