Please ensure the product(s) that you are going to buy fits the brand, model and part number of your device.

Specifications:

Battery Type: Li-ion
Color:  grey
Dimension:  122.00x80.40x20.40 mm
Capacity:  4000.00 mAh
Volt:  10.80 V
Replace battery part number: 
661-1764, 661-2472, 661-2569, 661-2672,
661-2994, 8403, 6612472, A1008, A1061,
M7692J/A, M7698J/A, M7699J/A, M8403,
M8433, M8433G, M8433G/A, M8433G/B,
M8520J/A, M8597J/A, M8597J/C,
M8597LL/C, M8598J/A, M8599J/A,
M8599J/C, M8599LL/C, M8600J/A,
M8600LL/A, M8602J/A, M8602LL/A,
M8626G/A, M8626GA, M8956, M8956G,
M8956G/A, M8956J/A, M9164LL/A, M9337,
M9337G, M9337G/A, M9426LL/A
This battery is also compatible with the following models : 
iBook 12-inch Dual USB
iBook 12.1" Screen Dual USB iBook 32 VRAM
iBook Crystal White Series
iBook Late 2001 Model
iBook Opaque White 16 VRAM
iBook Snow White Series
APPLE iBook - 12" LCD Series
iBook G3 12 M7692J/A " iBook G3 12 M7692LL/A"
iBook G3 12 M7698J/A", iBook G3 12 M7698LL/A"
iBook G3 12 M8520J/A", iBook G3 12 M8520LL/A"
iBook G3 12 M8597J/A", iBook G3 12 M8597J/C"
iBook G3 12 M8597LL/C", iBook G3 12 M8598J/A",
iBook G3 12 M8599J/A", iBook G3 12 M8599J/C"
iBook G3 12 M8599LL/C", iBook G3 12 M8600J/A"
iBook G3 12 M8600LL/A", iBook G3 12 M8602J/A"
iBook G3 12 M8602LL/A" ,iBook G3 12 M8758*/A",
iBook G3 12 M8758B/A*", iBook G3 12 M8758J/A",
iBook G3 12 M8758LL/A", iBook G3 12 M8758S/A",
iBook G3 12 M8758T/A*" ,iBook G3 12 M8758Y/A",
iBook G3 12 M8860*/A" , iBook G3 12 M8860B/A*",
iBook G3 12 M8860J/A", iBook G3 12 M8860LL/A",
iBook G3 12 M8860S/A", iBook G3 12 M8860T/A",
iBook G3 12 M8860Y/A" ,iBook G3 12 M8861*/A",
iBook G3 12 M8861B/A*" ,iBook G3 12 M8861J/A",
iBook G3 12 M8861LL/A" ,iBook G3 12 M8861S/A",
iBook G3 12 M8861T/A" ,iBook G3 12 M8861Y/A",
iBook G3 12 M9018*/A" ,iBook G3 12 M9018B/A*",
iBook G3 12 M9018J/A", iBook G3 12 M9018LL/A",
iBook G3 12 M9018S/A" ,iBook G3 12 M9018T/A*",
iBook G3 12 M9018Y/A" ,iBook G4 12 M9164LL/A",
iBook G4 12 M9426LL/A",iBook G4 12 M9623",
iBook G4 12 M9623*/A", iBook G4 12 M9623CH/A",
iBook G4 12 M9623LL/A",iBook G4 12 M9623X/A",
iBook G4 12 M9623ZH/A",iBook G4 12 M9846*/A",
iBook G4 12 M9846CH/A",iBook G4 12 M9846LL/A",
iBook G4 12 M9846X/A", iBook G4 12 Series",
iBook M7699J/A, iBook M9426ZH/ 

laptop batteries have two main ratings on them: Volts and Amperes. Because size and weight of laptop batteries is limited when compared to larger batteries such as car batteries, most companies show their ratings with Volts and Milliamperes. One thousand Milliamperes equals 1 Ampere. When buying a battery, select batteries with the most Milliamperes (or mAh). Batteries are also rated by Watt-Hours, perhaps the simplest rating of all. This is found by multiplying the Volts and the Amperes together. For example:

14.4 Volts, 4000mAh (Note: 4000mAh is equal to 4.0 Amperes).

14.4 x 4.0 = 57.60 Watt-Hours

Watt-Hours signifies the energy needed to power one watt for one hour. This laptop battery can power 57.60 watts for one hour. If your laptop runs at 20.50 watts, as an example, this laptop battery could power your laptop for 2.8 hours.

There are several steps you can take to help you get maximum performance from your laptop battery:

Prevent the Memory Effect - Keep the laptop battery healthy by fully charging and then fully discharging it at least once every two to three weeks. Exceptions to the rule are Li-Ion batteries which do not suffer from the memory effect.

Keep the laptop Batteries Clean - It’s a good idea to clean dirty battery contacts with a cotton swab and alcohol. This helps maintain a good connection between the battery and the portable device.

Exercise the Battery - Do not leave the battery dormant for long periods of time. We recommend using the battery at least once every two to three weeks. If a laptop battery has not been used for a long period of time, perform the new battery break in procedure described above.

Battery Storage - If you don’t plan on using the laptop battery for a month or more, store it in a clean, dry, cool place away from heat and metal objects. NiCad, NiMH and Li-Ion batteries will self-discharge during storage; remember to recharge the batteries before use.

Upgrade my APPLE iBook G3 12 M8597J/A M8597J/C M8597LL/C M8598J/A M8599J/A M8599J/C battery from NiMH to Li-Ion

NiCad, NiMH and Li-Ion laptop batteries are all fundamentally different from one another and cannot be substituted unless the laptop has been pre-configured from the manufacturer to accept more than one type of battery chemistry. Please refer to your manual to find out which rechargeable battery types the laptop device supports or use our Battery Finder above to find all the compatible laptop batteries for your device. It will automatically list all of the battery chemistries supported by your specific device. If your device does allow you to upgrade the battery from NiMH to Li-Ion, you will typically get longer run times.

For example, if your laptop uses a NI-MH battery that is 9.6 Volts, 4000mAh and the new li-ion laptop battery is 14.4 Volt, 3600mAh, then you will obtain longer run time with the li-ion battery.

Example.

Li-Ion: 14.4 Volts x 3.6 Amperes = 51.84 Watt Hours
Ni-MH: 9.6 Volts x 4 Amperes = 38.4 Watt Hours
The Li-Ion is stronger and has longer run time.