adapter M12 x 1.5-10mm barb https://www.efihardware.com/products/1305/adapter-M12-x-1.5-10mm-barb
Fits to the outlet of Bosch fuel pumps with M12 x 1.5 Thread.
Note this replaces the one way valve on some Bosch fuel pumps that normally uses a banjo fitting with cap nut. The one way valve ensures that pressure remains in the fuel line and fuel rail up to the fuel pressure regulator. This improves restarting the engine as the system is already primed and up to pressure. It also prevents the fuel boiling in the fuel rail in hot conditions.