Shades Fragranced Refill Cannisters are formulated to remain suspended in the air for many hours, eliminating mal-odours. One unit, suitably placed, will fragrance approx. 6000 cubic feet. Each aerosol delivers 3000 applications, set to spray at 20 minute intervals. One aerosol will last approx. 6 weeks. Avaialble in a variety of fragrance options.