Cartridges are infused with high-quality perfumes, complemented by an integrated internal fragrance core, combining to diffuse powerful key fragrance notes that subtly change, avoiding fragrance fatigue. Fragrances last up to 30 days. No aerosols, batteries, liquids or propellants. VOC exempt. Solid cartridge, won't leak or spill. Coverage up to 17,000 cubic feet specifically for medium to large spaces.