So there isn't much other than the obvious to say about one of these batteries.
They are easy to find and cheap enough to buy if you need to replace your old one. They are sturdy and hard wearing and easy to detach from the laptop itself.
I didn't find that mine needed replacing however I would be confident to buy one online quite quickly and easily without any worry.
I found my batter charged very quickly in comparison to my older model Apple MacBooks (yes I have/had many in my time). I also didn't need to keep my power source cable plugged in at all times. Once my battery was charged I found it lasted quite a while even when I was surfing the internet and writing out invoices on app's I had.
The technical facts are quoted from Amazon - http://www.amazon.com/Battery-Apple-MacBook-17-Inch-MA611B/dp/B009RBVF98
- LB1 High Performance Utimate Power Series Commercial Grade Laptop Batteries for Apple MacBook Pro 17-Inch MA611B/A are custom manufactured to be 100% compatible and optimized for your Apple MacBook Pro 17-Inch MA611B/A laptop.
- Utimate Power Series Notebook Battery for Apple MacBook Pro 17-Inch MA611B/A utilizes high quality grade "A" cells for higher performance longer life and more reliability.
- Utimate Power Series Computer Battery for Apple MacBook Pro 17-Inch MA611B/A meets and/or exceed OEM specification and will not void your original manufacturer warranty.
- Batteries capacity: 6600 mAh | Chemistry: Li-ion Polymer| Voltage: 10.8 Volts | Cells: 3 | wHr: 71.
- Fast charging. Low power consumption. Built-in protection circuit ensures both safety and stability.