Has enhanced fragrance bead technology for improved overall performance and longevity. As the soft gel evaporates, the pearls begin to release their encapsulated fragrance oils. This natural, slow releasing action helps extend the performance of the gels for up to 30 days. As the pearls release the fragrance, they will begin to shrink for optimum performance. Replace gel cups 30 days from installation. Water-based. Environmentally safe. Water soluble. Non-toxic and non-flammable. 2 oz cups.