Advance Nilfisk Carpet Twin Vacuum Bags For the Advance Nilfisk Carpet Twin 14 and 18 Models of upright vacuums, this is a generic 9 pack of EnviroCare Nilfisk Carpet Twin Vacuum bags - replaces part# 703768. Each bag is constructed with an inner liner of electrstatically charged material trapping even microscopic particles as small as 1 micron. These bags are designed to meet exact OEM specifications for performance and installation.