Fresheners are products that can release the chemicals they contain into the air intended to dampen bad smell so as to make the room/surrounding comfortable. Forms of freshener in the market are solid (used for cabinets and toilets), liquid, spray and gel. Fragrances, gel is usually laid out by hanging or placed in a place. Gel Air fresheners keeps rooms, offices and cars always scented. The advantage it has over the spray air freshener is it's continuous diffusion . Once the container is opened, the scent diffuses into the whole space. You don't need to always apply it.