Ryobi tools batteries

Speaking of the Ryobi cordless power tool
chain, I see there are no less then five
different batteries! All are 18V Lithium but
the Ah's are 1.3, 1.5, 2.5, 4.0 and 5.0.
What does that mean? Do you get more power for
a single drill or cut or whatever or can you
just do the same thing more times
before recharge?

--
underground experts united
http://user.it.uu.se/~embe8573