Mercedes Benz selected a three stage diesel fuel filtration system.

#1. This is generally called a fuel tank strainer, but it is a filter.

#2. This is a disposable in-line particle filter.

#3. This is the final filter before the HEART of your diesel, the injection pump.

Filter #1 catches the largest particles.
Filter #2 stops medium particles.
Filter #3 does double duty, micron filtration, and a very small amount of water separation = measured in CC.

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