Three layers for better dust retention. 99 percent of all particles remain in the dust bag. Replaces quickly, cleanly and easily. As you pull the tab to remove the bag it automatically closes and seals in the dirt. 1-gallon/3.5-liter useful capacity. Compatible with Formula and Compact vacuums. Replaces quickly, cleanly and easily. Compatible with Formula and Compact vacuums. Three layers for better dust retention. 99 percent of all particles remain in the dust bag. As you pull the tab to remove the bag it automatically closes and seals in the dirt. 1-gallon.