Good advice here from all responses. I have both kgo and ego batteries, all have 5-click on/off. Kgo and ego batteries are essentially the same thing. I believe Kgos come in one length (more length = longer life between charges) - 1100mah. Egos are available in several lengths - 650mah, 900mah, 1000 or 1100mah. The kgos do put out a little higher voltage.
I stand corrected, I see some vendors now have the kgos also in 650mah (shorter length). But the 1100s are the way to go.
Darkcityvapor.com has a great deal on kgo 1100 kits for $44.