Neutop Replacement Front Wheel Caster Ball Assembly Compatible with All iRobot Roomba 500, 600, 700, 800, 900, e, i, & j Series Robot Vacuums, 2-Pack.: Amazon.com: Industrial & Scientific
How to Clean the Front Caster Wheel | Roomba® 600 series | iRobot® - YouTube
iRobot Roomba 655 Pet Series Front Caster Wheel Replacement - iFixit Repair Guide
iRobot Roomba 655 Pet Series Front Caster Wheel Replacement - iFixit Repair Guide