[suicideneil]

C rating = discharge rating- as in 5000mah x 20c = 100amps continuous output.
Voltage is 3.7v per cell, the S next to the 2,3,4,5,6 means Series, as in the number of cells in series to give you a total pack voltage.

You want a single 4s or pair of 2s in series for your setup ideally.