5 micron filter bags.  Comes with 5 bags.  Collect even the smallest debris with these bags.  Works with the 4000, 4001, and the 8000 filter paks.

We recommend 25 micron if using plastic media and a 15 micron if using ceramic media. All filtration systems come with a 15 micron if you'd like to use the same filter bag.

A 5 micron is the smallest hole size and lets less particles through. A 100 is the largest hole size and lets the most particles through.