Welcome to BLF!
Well you bought it, is it really $100+?
Hopefully they put some real Cree LEDs in there.
( Can you cancel? The Supfire M6 from Mountain Electronics is cheaper and probably better (I googled and found the s99 here so this is what I am basing this on) )
Button top 18650 is what you need, do you know anything about Li Ion cells?
Please read Lithium-ion battery safety 101 and let your wife read it too 