Hi 2Goofycampers,
Although some off-brand bags may fit your Heritage II, we highly recommend purchasing the bags that are most appropriate Kirby systems. We have several different kinds, including ones with great ratings for HEPA filtration.
We recommend reviewing the ones right for you by contacting your local distributor or ordering directly from The Kirby Company at 800-437-7170. Please let us know if you have any questions!
Best regards,
The Kirby Company