Go to Amazon.com : http://www.amazon.com/gp/product/B00D2PZZV4?tag=theatrecat-20
Powerextra? 14.4V Replacement Battery Compatible with Irobot Roomba 4000 4100 4105 4110 4130
Brand new replacement batteries that are manufactured to meet the specifications of the original
High quality high capacity battery for longer running timeconvenient to use
Ni-MH battery 35Ah Capacity 144V made with high quality battery cells
50 percent greater useful life than original Roomba batteries Custom packaging
Compatible with iRobot Roomba 400 Series Floor Vac models Advanced Power System APS Battery