The Aquasana AQ-4000 Replacement Water Filter is a brand new, open box product that includes 2 filters. Made of carbon fiber with a filtration method of carbon/charcoal, this filter is compatible with models AQ4000, AQ4600, and AQ4601. The white and blue colors make it easy to identify and use in your water purification system. Perfect for keeping your water clean and fresh, this Aquasana filter is a reliable choice for improving the taste and quality of your tap water.