The 4/7 Atom are all Mule' and have been terrific in my use with them.
I was actually shocked somewhat when I got my first aaa Atom,it is a 2 speed Mule with a 219 emitter,Simple and sweet is all I can say.
Somehow the light from this tiny light is the equal of many much larger and more pricey models that I own and thus I carry the Atom over the others many days.
Also sold in aa and pretty cheap too just not made in the USA.
I have a Peak Eiger 219 Mule too and it has never really worked since the day I got it.
I also have a few of the ZL Headlamp Mule and they too are amazing as are every ZL that I own.