HQRP Humidifier Wick Filter improves the efficiency of your humidifier by trapping mineral deposits from the water. This triple-layer humidifier filter helps control dust and dirt build-up and prevents impurities from spreading by passing air through the filter, also remove household odors. For optimum performance, humidifier filter should be replaced at the beginning of each season and then every 4-6 weeks, depending on usage and hardness of water. Replacement for Bionaire part BWF100, BWF100CS, BWF100-CN / Holmes HWF100, HWF100CS, HF235 Type E Filter. Compatible with Bionaire Humidifiers BCM730, BCM730B, BCM730B-CN, BCM740B, BCM740W, BCM7305, BCM7305RC, BCM7305RCB, BCM7307, BCM7308, BCM7309, BCM7510, BCM7203, BCM7203RC, BCM7204, BCM7205, BCM7207, BCM7255; BCM630, BCM630B, BCM630B-CN, BCM645, BCM646, BCM646C, BCM646BF, BCM655, BCM657, BCM658, BCM658C, BCM658SC, BCM600, BCM4600, BCM4655, BCM5520, BCM5521, BCM5555, BCM6000, BCM6010, BCM6010RC, BCM6610RC, etc.