2s2p means that the lipo has 4 cells total. 2 cells are wired in series "s" to get the proper voltage while maintaining the same capacity rating (amp hours). Where the other two cells are wired in parallel doubling the capacity (amp hours) of the battery while maintaining the voltage of one of the individual batteries. Basically means you have 2 cells that are 2500mah wired into parallel to make a 5000mah then 2 cells that are 3.7v will become 7.4v when wired in series. thats how you get a 7.4v 5000mah lipo.