Neato XV Series 4400 mAH Lithium-ion battery 2 pack with 3 free HEPA filters 4x longer battery life than Neato batteries and all aftermarket replacement NiMH batteries. Remains at 80% capacity after 800 charge cycles We guarantee this Li-ion battery has superior performance than any NiMH battery in market. Save money by using a lithium battery (800 cycle times, 1 Lithium battery = 4 NiMH/NiCd batteries). FULLY compatible with the original charger and vacuum. Built-in over-charge, over-discharge, over-voltage, over-current, and over-temperature protection circuit. Risk free 30 days money back guarantee, and 18 month warranty.