Fuel Injectors: Types, Function & Replacement

First of all, I would like to give Rainer a big compliment.
The ordering process in the shop works perfectly; you are constantly informed about the status of your order via email, and it's incredibly fast.
In this specific case, we're talking about nozzles.
My Audi 80B4 1Z, with approximately 240,000 km, had a "problem" with cold starting (glow plugs were fine), produced a cloud of smoke, and made a knocking noise, etc.
As can be seen in the attached images, it's no surprise that there was also spatter and carbon buildup (all 4 pieces looked the same).
The 0.2, 5 size injectors were installed, the car is almost unrecognizable, there is no smoke, only the typical diesel knocking sound, the performance is noticeably higher while simultaneously having less fuel consumption , approximately 0.5 liters per 100 kilometers.
I can only recommend it to everyone; those few euros are always worth it compared to replacement nozzles.