Citrus refill is designed for use in the Scott Essential Continuous Air Freshener System. One easy-to-install cartridge gives you continuous, unobtrusive dispensing (unlike sprays). Automatic air freshener (sold separately) acts as an effective odor neutralizer that works for 60 days. The entire system is economical and takes less than 1 minute to install. Passive system design is nonaerosol so it doesn't contain propellants or added VOCs.