Double your battery life when traveling with an extra battery. This Apple Rechargeable Battery is a lithium polymer battery.
Customer Rating: 



Review Summary: Works
Review: My original battery lasted about a year with light use. The new battery gives me about 2 1/2 hours time, less than I expected from the Apple hype. A bit over priced, as all Apple products are, it matches my MacBook Pro perfectly.
Customer Rating: 



Review Summary: Performs as expected
Review: I purchased this item as a replacement for 1.5 year old battery that came from the manufacturer. My previous battery had something wrong with it, in a period of 2 months, it went from 85% health, to about 40% health, and then in a period of about 2 days it dropped below 20% health. This made it so i was getting < 1 hour battery life which was unacceptable. I was at about 290 cycles when it was at 40% health, and I called apple, but they said since it's been over a year they wouldn't do anything about it (which contradicts a lot of things I've heard from other users experiencing the same issues).
At any rate, my new battery is here, popped it in, drained it, gave it a boisterous charge, and now i'm getting somewhere between 3.5 to 4 hours battery life on a full charge. I was appalled after 1 cycle though, the health dropped to 99%, but now I'm nearing 20 cycles and it's still at 99%. Works for now, hopefully this one will last the rated 300 cycles (apple says 300 cycles should have a health of 85% still).
Customer Rating: 



Review Summary: Really good battery
Review: Although it didn't come in a original Apple package (small gray box instead) and was produced in 2006 (I bought it in Nov 2008) it had 0 cycles and lasts for 3,5-4 hours on my MacBook Pro 15". So far so good!
Customer Rating: 



Review Summary: Lasts about 1 Hour
Review: I've had several of these now and all have performed very poorly despite following all recommendations about cycling. Out of the box they've lasted about 2.5 hours and quickly degrade to about an hour. Sadly the alternatives aren't much better (I've tried third party batteries too).
Customer Rating: 



Review Summary: Replacement Battery
Review: The battery works great. It arrived when it was supposed to. I am very happy.