Blueair genuine replacement pre-filter in Lunar Rock (Light Gray) color for the Blue Pure 211+ air purifier. Form meets function in Blue Pure 211+‘s premium, colorful pre-filters. The fabric allows you to customize the color to match your style, as well as extend the life of the primary filter, catching large airborne particles such as dust, lint, pollen, and pet hair. Vacuum the exterior of the fabric pre-filter to remove visible dust and dirt as often as you'd like. Removable, washable, and reusable the pre-filter is designed to be used again and again. When it requires a deeper clean, throw the fabric in the washing machine on a gentle, low-temperature cycle. Hang to dry.