duogreen Robotic Vacuum Replcement Filter for iRobot Roomba 700 Series 780, 770, 760, Set of 4 Duogreen replacement filter for irobot roomba 700 series Compatible with irobot roomba 700series 780, 770, 760 Part#21899 peak perfomance for 2-3 months. 2 replacement sets of 2 hepa filters