COMPATIBLE WITH BLUE PURE 211 plus: Genuine Blueair Replacement Pre-filter in Diva Blue color for Blue Pure 211 plus air purifiers (non-auto); not compatible with Blue Pure 211 plus Auto air purifier FILTER LIFE EXTENSION: Colorful fabric pre-filter extends the life of the primary filter, catching large particles such as dust, lint, pollen and pet hair NO COMPARISON: Genuine Blueair pre-filters are specifically designed to enable optimal air flow and performance over time; When combined with electrostatic filtration, this results in faster and quieter cleaning than traditional HEPA filtration CLEAN WITH EASE: Vacuum the exterior of the fabric pre-filter to remove visible dust and dirt as often as you'd like and as-needed based on indoor air conditions DESIGNED FOR REUSE: When the pre-filter requires a deeper clean, wash on a gentle, low-temperature cycle in the washing machine CUSTOMIZE WITH PREMIUM COLORS: Available in five premium pre-filter colors; Dark Shadow (Gray), Diva Blue, Lunar Rock (Light Gray), Crystal Pink, Buff Yellow