20" x 4.5" Filters cartridge range
These type suite the Jumbo 20" housings, usually that come in white or blue/black colors, and will be found on tank water applications or installed on town supply with carbon filtration to remove chlorine.
Our range of quality 10" jumbo filters carry the NSF rating for quality assurance. Cheaper filters tend to block quicker and degrade inside the housings.
If you have have 2 filter housings it is referred to as step filtration. Starting at a higher micron rating on the inlet and reducing down to the smaller micron size in the next filter. A common step filtration in micron size is 20 micron then down to 1 micron in the following filter.
Reducing down to 1 micron will remove Giardia from the water. So there are some major health benefits by have a twin system filtering down to 1 micro.