Flylinktech 14.4v Ni-Mh Battery for iRobot Roomba R3 500,600,700,800,900 Series 880 510 530 531 532 533 535 536 540 545 550 552 560 562 570 580 595 620 630 650 660 760 770 780 790 870 900 3.5Ah