Dodge/Cummins “Connector” Tube Cut-away.
The edge filter is a safety feature built into the connector tube. It’s purpose is to break up contaminates larger than 50um which would otherwise enter the fuel injector, possibly causing damage such as continuous injection or blocked nozzle holes which can possibly cause catastrophic engine failure. The edge filter cannot prevent all injector damage from contaminated fuel – contaminants smaller than 50um can still damage common rail injectors and reduce their life expectancy.
Replacing the connector tubes when you replace injectors is a recommended repair. The removal method is to press the edge filter out of the inlet end of the injector. Once removed the connector tube must be replaced. (We always advise replacing connector tubes when replacing injectors rather than reinstalling the old ones).