Pop & twist removable seal. This design allows you to open your refill cartridge with another cartridge! Ready for use in seconds. No more knives needed for cutting, making it safer to use. One of the strongest seals in the industry to prevent fragrance leakage. No more excess outer packaging. A natural product, made with botanical fragrance oils and organic ingredients. VOC compliant. Last a full 30 days. Fit in all F-Matic Air Renewal Dispensers.