Genuine Simplicity Central Vacuum Bags (3pk) are multi layer cloth construction for quality air filtration and rip proof durability. These bags are designed to fit all Simplicity bagged central vacuum units. To help ensure optimal filtration and maintain maximum suction, users should change the vacuum bags with regularity. When the bag over fills, the central vacuum motor must work harder causing poorer performance and shorter lifespan of the unit. Genuine Part # SCB-3