A quick note about batteries. mAh is a judge by which you know how long your battery will last. Just know, the higher the mAh, the longer the battery will last. The time your battery will last, however, is contingent upon the amperage you are pulling from your battery; the lower the ohm, the more amps, the shorter your battery life is.
Ego Style batteries are beginner, sharpie sized, batteries. These usually have either a nominal 3.7 volt output but some come with Variable Voltage in the form of a twister knob on the bottom of the device. These CANNOT handle sub-ohm builds and should only be used above 1.0 ohms. Popular brands include Kanger, Vision, and iTaste.
ICR is a VERY unsafe battery to use for vaping. These batteries have a chemistry that when it goes into Catatrophic Thermal Failure it can explode rather than just “vent”. They’ve mostly made their way out of the vape scene but PLEASE if you see someone using an ICR let them know there are better options.
IMR, Li-Ion, and LimN batteries are the standard for any “Big Battery Mod” like the Evic or the DNA20/30 devices, or mech’s. These are the safest option we currently have available to us on the market. Pupular brands include but not limited to Sony, Efest, AW and Panasonic.