Item Type: Air Purifier Filter Material: High Efficiency Particulate Air Filter, Cotton, Activated Carbon Color: Blue Applicable Model: For Xiaomi 1 2 3 4 2S PRO (not suitable for Xiaomi 4 lite) Feature: With RFID Package List 1 x Air Purifier Filter 1. It is recommended to replace the filter every 3 to 6 months, or depending on the use.2. This product is not suitable for Xiaomi 4 lite. 1Applicable Models: This filter is applicable for Xiaomi 1 2 2S 2H 3 3H PRO MAXIMUM, not suitable for Xiaomi 4 lite. 2Better Performance: By replacing the old filter, the air purifier can achieve continuous and qualitative air purification. 3High Efficiency Filtration: Using triple filtration system, with 99.97% high efficiency filtration, making the living environment safer and cleaner. 4Professional Made: This filter is specially made for replacing your old filter. It is recommended to replace your old filter every 3 to 6 months. 5Easy Installation: The filter is very easy to replace and install on the air purifier, you can finish the installation quickly.