Usage Tips:Optimal Performance: Designed specifically for the Blue Pure 311 and 3410 models, these replacement HEPA composite carbon filters your air purifier operates at efficiency. Capture up to 99% of airborne , pollutants, and formaldehyde for a cleaner, healthier home environment. Long-Lasting Use: Each filter offers a prolonged lifespan with easy maintenance. Recommended replacement every 3 months ensures optimal air quality. Reminder: For continued excellent performance of your air purifier, regular replacement of the filters is crucial. This not only maintains the quality of the air but also the efficiency of your purifier. Note: These are products, products. Color: As shown Material: Plastic + HEPA Package Contents: 2 * HEPA Composite Carbon Filters Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.