4-in-1 Purification System: The air filter includes a an efficient particulate air filter, pre-filter, and cold catalyst filter to protect against dust and pet dander. Filter Replacement Reminder: The air filter needs to be replaced periodically; when the filter indicator turns red, it is time to replace it to maintain optimal performance. Eco-Friendly Design: The air purifier filter is designed to be eco-friendly, featuring a washable pre-filter and a durable frame for long-lasting use. Additional Features: Includes a washable pre-filter and a solid frame for durability, backed by dedicated customer care support.