iRobot Authentic Replacement Parts- Roomba e, i, & j Series Replenishment Kit, (3 High-Efficiency Filters, 3 Edge-Sweeping Brushes, and 1 Set of Multi-Surface Rubber Brushes),Green - 4639168 - Walmart.com
Best Buy: HEPA Filters for iRobot Roomba 800 Series (3-Pack) White 4415864
Amazon.com - JoyBros 12-Pack Replacement HEPA Filter for iRobot Roomba evo E&I&J Series E5 E6 i1 i2 i3 i3+i4 i4+ i6 i6+ i7(7150) i7+(7550) i8 i8+ J7/+Robot Vacuum
Are Third-Party Roomba Vacuum Filters Safe to Use? | Wirecutter