Tenergy Li-ion 14.8V 4400mAh Replacement Battery for iRobot 400, 4000, 4100, 4150, 4210, 4230, 4260, 4290, 4300, Discovery, Dirt Dog, Scheduler, Create and Burgundy Series Longer Runtime - Tenergy Li-ion 14.8V 4400mAh replacement battery has 40%-50% longer run time than the iRobot Roomba original 3000mAh battery. Direct Replacement - Designed as a direct replacement for iRobot (Roomba) 400, 4000, 4100, 4150, 4210, 4230, 4290, 4300, Discovery, Dirt Dog, Scheduler, Create, and Burgundy Series. Smart and Safe - Built-in protection prevents damage caused by overcharging, overheating, and short-circuit. More Charge Cycles - Up to 800 charge cycles compared to 200 cycles for the original NiMH Battery. (Charge cycle is from discharge to full recharge) Longer Storage Time - The ultra low self-discharge rate (1% per month) eliminates the need to keep the battery charging all the time. This will save energy and prolong the lifetime of the battery.