Each set contains one automatic aerosol dispenser,2 No.1 batteries and 1 air freshener.This automatic aeroso dispenser can spray out fragrance automaticly.And have 3 work status:DAY(works when there is light,stops automaticly when there is dark);NIGHT(works when there is dark,stops automaticly when there is light);21H(works round the hour).3 interval for you to choose:5 minus(sprays every 5 minutes);15 minus(sprays every 15 minutes);30 minus(sprays every 30 minutes).