You can expect about 3-5 hours of run time with this Asus U47A battery when new. You can get even longer battery life by dimming your screen and closing unused programs.
The battery part number printed on the battery label is so tiny, you will need a magnifying glass to see the battery part number. If your model matches the listing of Asus machines at the extreme bottom of this web site, this is the correct battery for your Asus.
Replaces these Asus U47A battery part numbers:
A32-U47
A41-U47
A42-U47
Q400A
U47VC