✅【PERFECT FIT】Compatible with Blueair Blue Pure 311 Auto⭕ air purifier. NOT compatible with Blueair 311❌ ❎【NOTE】Not compatible with Blue Pure 311❌, 311i Max, 311i+ Max, 211, 211+ Auto, 211i Max, 411, 411 Auto, 411i Max, 511, 511i Max, Mini Max air puri-fier 【AllergenBlock Design】Effectively traps more than 90% of AllergenBlock particles. In addition to efficient performance, it can also save up to 10% of automatic delivery filters and extend machine life 【True Air Filter】Our 311 Auto replacement filter made of air filter and a high-efficiency activated carbon filter for good clean filtration and performance 【OPTIMAL PERFORMANCE MAINTENANCE】For the ongoing top performance of your Blue Pure 311 Auto Air Puri-fier, based on actual usage the filter should be replaced within 9 months 2 Pack Blue Pure 311 Auto AllergenBlock Filter