The normal Subtank mini fit it, IIRC. I bought the mini atty and fogger, then when the microstick arrived it was a d'oh moment [emoji3]
@kross8 - updated info
Attached is a photo.
It takes an 18500 battery (I've got a purple Efest for it; per Mooch it's an honest 10A 1100mAh).
It definitely holds a true 22mm tank. The photo is with a serpent mini inserted. The serpent mini is actually too short, was just used for diameter check. I'm pretty sure a Subtank Mink was good for it, but darned if I can find one hanging around.
The fire button has a threaded, rotating, lock (the outer portion of the fire button). It needs to be lubed to work well
Anyhow, it's in the PIF stack.