Blueair 500/600 Series HEPASilent Particle Filter(Includes 3 Filters)

Blueair 500/600 Series HEPASilent Particle Filter. Compatible with these Blueair purifiers: 501, 501B, 503, 550E (any model number beginning with a 5); 601, 603, 650E (any model number beginning with a 6)