Aluminum reinforcement design ensures extended life; Up to 150% more strength | Micro-Free feature and Best Air technology traps impurities and protects against bacteria, microbes, and other contaminants | Specially manufactured woven honeycomb pads allow for the maximum absorption of water; Ensuring the best possible humidity output | Chlora-Clear Plus C technology allows the filter to neutralize chlorine in the water | 4 filters per box; Made in the USA