Well.. For Example 5000mAh 2s 25c Ofcourse you know what "mAh" is, 2s,
3s, 4s etc is 2s 2 cell pack(7.4v), 3s 3 cell pack (11.1v), 4s, 4 cell (14.4v) and so on The "C" rating is the discarge rate. c rating divided my mAh rating gives you cont. discharge rate. 5000mAh 20c pack is 100 amps continous discharge.
I hope this helps