Blueair 500 Series Replacement Particle Filter 3 Filters in Package 13 x 9.5 x 8.5 Compatible with all Blueair 500 & 600 Series Air Purifiers Replacement for: 501, 503, 550E, 601, 603, 650E 99.97% of 0.1 micron particles on Speed

One Replacement filter ensures up to 6 months of use 3-stage progressive filter First layer absorbs large particles such as pollen and dust while the second and third layers capture smaller particles, including bacteria.

Exhaust filter design Resists loading or clogging to continue filtration at peak performance levels.

Additional part numbers: 500600PFK, 501PFK