Amazon.com - Replacement for iRobot Roomba 581 - Kit Includes 1 Battery, 1 Filter, 1 Bristle Brush, 1 Flexible Beater Brush and 1 6-Arm Side Brush
Amazon.com - Replacement Parts for iRobot Roomba 500 Series Roomba 555 560 561 562 570 581 Vacuum Cleaning Robots Other Models with Green or Red Cleaning Head.
Completely mechanicaly and cosmeticaly refreshed roomba 581 : r/roomba