Holmes HWF100-UC3 Extended Life Humidifier Filter, 3 Pack
The HWF100 filter improves the efficiency of your humidifier by trapping mineral deposits from the water. It is treated with Arm & Hammer Baking Soda and Microban Antimicrobial Product Protection for added peace of mind. Humidifier filters should be replaced at the start of every season and then replaced every 2 to 4 weeks depending on the usage and hardness of the water.