These Donaldson filters have better filtration than airdog and are less expensive.
The Donaldson fuel filter is 3 micron after 1st pass where Airdog is only 5 micron after first pass. After multiple passes the filtes will be able to get even more contaminants out, but the initial pass is called teh "Absolute" rating.
The Donaldson water separator is better at removing water from the fuel and significantly better at removing emulsified fuel/water.
