"eGo" style 510 auto-regulated batteries
This style of battery has a 510 thread in the middle, with another larger thread on the outside. These batteries work fine with the kits they appear in, but this is the most basic, zero control, vape battery source. Light on amperage but light in size and weight.
18650/26650 Battery Suggestions
Battery cells provide the rechargeable amperage necessary to drive some really amazing coils - coils that just will not fire with an eGo style battery. This kind of vaping is something every vaper must experience before deciding on a "slim" device.