Their description:
Product Description
This 61-watt-hour rechargeable lithium ion battery provides up to 6 hours of operation depending on battery saving features used and system configuration. This battery is compatible only with 14-inch iBook having two USB ports…. More >>
Go & get it here - i can recommend it:
Apple Extra Rechargeable Battery for 14″ iBook Computers
This is a battery for an iBook. It stores energy for use when you are not near a power outlet or do not have your power cord. In terms of its storage and later release of energy, this battery is batterytastic. Thus far it performs like the original battery I had with the machine, so I’m getting about 4.5 hours per charge if not using a million applications and Airport (two activities that will drain the battery quickly).
Works as described initially, but even with meticulous care (as described on Apple.com) the life is timed in months before you can’t hold a full 5-6 hour charge. I’ve had mine for less than 6 months and I’m already at 4 hours with a full charge doing nothing but email and internet. On the other hand, I have nothing to compare. Also, you may add some extra life by turning off the Airport when not in use.
Hope this helps.