. These charcoal-lined HEPA media bags fit Riccar Prima canister vacuums. There are 6 in a pack We guarantee a proper seal and fit of the bags to eliminate dust from exiting any leaks and making sure the bag fits the connector well. Our bags are designed to match our vacuum performance. Alternates may or may not have the same back pressures and/or filtration capability Our bags are made to work with the stitching and pressures in our product. If the stitching tears, the bag then has a hole and will not filter the air properly. Our bags are tested to match the vacuums for fit and still provide the correct gaps to ensure optimal air filtration. If another bag is too small or too large, or the wrong thickness, it can cause gaps and seals that can degrade the performance of the machine