"Bought this battery with my X220 a couple of years ago. It's lasted 2.5 years so far and I have had no issues with it. Yes, it adds a little bulk to your laptop but I was able to get a full day of use out of my PC with this external when coupled with the extended battery which was what was most important to me for transcontinental flights, days full of business meetings, and other activities. Would I buy it again? Maybe - it was somewhat expensive but considering how far CPU performance has evolved, it may not be necessary any longer to buy this type of accessory. Note: your experience may vary."
"This product was dead on arrival and Lenovo won't replace it. They bounced me all over the world from China to North Carolina on the phone and never did resolve the problem. Of course their solution was to go ahead and order and pay for a new one like it was my fault they ship bad products. I'll be writing reviews in all the computer magazines about Lenovo and filing a complaint with my State's Attorney General's Office."