If you have the InterVac central vacuum system you can access them at
www.intervacdesign.com or call toll free 888-499-1925 for bag replacements for your unit. Often various RV shows have InterVac reps available with their accessories and offer show prices on such products. As Bingo related above, do a Google search for Intervac Dust bags. It will reveal Intervac company and others that sell these bags. You can decide who to order from because some vendors are a dollar or so cheaper than Intervac. Maybe Intervac will match these other lower prices. Good Luck.