The 4150-02 Clean Guard XL is a Reusable Maintenance Bag Specifically for use by HVAC Contractors to Clean Wall-Mounted Mini-Splits and Ceiling Cassette Systems with Nu-Calgon Cleaners/Disinfectants when the Indoor Coil and Blower Require Service. Clean Guard Installs in Seconds with its use of an Industrial Grade Elastic Collar that Simply and Automatically Adjusts around the Indoor Unit. There is nothing more Simple and Quick to use in the Market!