The factory coils on the Aero Mega are 2.0 ohms. They have the separate dual holes.
The factory coils on the Aero Mini are 1.5 ohms. They have the single large slots, as do the lower resistance and "Kanger Subohm" versions.
Well, things change ... As I said before ... I just got a new Mini and a Mega in the mail today.
The Mini has 1.5 ohm coils, and the Mega has 2.0 ohm coils.
However, both the 1.5 and the 2.0 have one slot on both sides of the coil housing .... Neither have the double holes on each side.
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EDIT: And the box (white box) of 5 replacement 2.0 ohm coils also have the single slot on each side too.
FYI ... The box shows 5 different ohms that obviously these coils can be purchased. They are 2.0, 1.5, and 1.2 ohm
They also have SubOHM of 1.0 and 0.8 ohm
My box was obviously checked 2.0