Several of Vaportek's products require cartridges. The Standard 100 gram, 90 Day Cartridge is compatible with the Optimum 4000, Restorator, and Restorator DUO. Cartridges are filled with an essential oil membrane. The oils "sweat" through the tiny membrane pores and are dispersed into the air as a dry vapor with the assistance of air movers or natural air currents. The Classic Neutral Cartridge is designed to tackle tough odors while imparting a neutral scent.