Light sensor mode saves fragrance & allows the machine to be operated in Day or Night mode automatically Works on two AA size Batteries Low power Consumption Energy Saving Environmental Multifunction Setting to Meet Different Demands both Aerosol can can in work in the same time or can work one by one the whole module can take it out if need to replace a new one Working mode option of Day, Night & 24 hours It's a Self Standing machine which can be Wall Mounted also Aesthetic design and features makes this Automatic Room Spray machine ideal for homes, offices, hotels, shops, hospitals and other public places.