The cover is the air freshener. This offers the most exposed surface area of any refill resulting in maximum fragrance release. The pre-set program is set so that throughout the course of 30 days, as the fragrance evaporates, the fan spins more frequently to keep the space smelling just right. Dry fragrance technology doesn't contain any acetone or propellants. Visual and audible replacement reminders. A new battery comes with every refill for simple maintenance. Made specifically for the Easy Fresh dispenser to freshen all your medium size spaces for 30 days. Easy Fresh is powered by a smart chip that controls the fan consistently, turning it sparingly in week 1, and gradually turning more frequently until week 4 when it runs constantly. Maintenance is easy, with the LED and audible reminders and a push button cover for quick removal and replacement. Easy Fresh refills are part of Fresh Product's closed-loop recycling program and are 100% recyclable.