This USB Charger Is For Charging An Ego Battery, With A Computer,
or car charger.
It Can Also Be Plugged Into The USB Port On The Wall Charger For
Plugging Into An Outlet
The 420 mah is for the larger batteries, 650, 900, 1100.
The 200 mah is for the 510 manual batteries that are the
size of a pen. Manual is with a button.
The 120 mah is for the 510 automatic batteries, that are
also the size of a pen. Automatic has no button.