I bought ANTRobut 4500mAh 14.4V NI-MH battery replace by Revain, but I'm really disappointed. The battery is specified as 4500 mAh. but that doesn't seem to be the case. A year ago I bought a PowerExtra 3800mAh battery. I compared the results on the same iRobot as shown below. PowerExtra 3800mAh (already used 1 year), full charge can work 1 hour 25 minutes. ANTRobut 4500mah (new) can only work 1 hour 5 minutes. It takes 3 hours to charge PowerExtra 3800 mAh to 100%, ANTRobut 4500 mAh (new) takes 8 hours. according to the data. ANTRobut maxium is only 3000mAh and the charging time is too long, it really doesn't show that it is a new battery. I trusted the ANTRobut brand and the package received looks like the Revain picture and arrives on time (which is good). but the above comparison results really can't give a good overview.