Upgraded my Delta AP400 dust collector to a Delta 1 micron bag. The original was 30 micron. The new bag is much thicker, so much that it stands up on it's own. The 30 micron bag snapped up when inflated and was as taught as a balloon. Despite being thicker, the new one is pretty much the same with the collector running or off so I guess that means the new bag has less resistance; a lot less resistance.
Link to product on Amazon: