Bosch RQV manifold pressure compensator diaphragm membrane 2420503019. This is a genuine Bosch part
If you prefer a cheaper good quality non genuine part we also stock these HERE
Commonly fitted to P7100 pumps / Dodge / Cummins applications
Item 6 in the exploded diagram
KHD-DEUTZ 1319321, 01319321
The diaphragm increases the optimum fuel delivered from the injection pump when the pressure in the engines inlet manifold rises with turbo boost. Split diaphragms result in significant loss of power.