The usage was done in a Nissan Qashqai. I had never used this particular additive before. The label states that it contains only "kerosene" (which is the fuel used by aircraft). I can't say that it saves fuel or adequately protects the car's fuel system, as it needs to be used for a long period of time to form a proper opinion. However, from the days that I have used it, I noticed that the engine makes less rattling/noise. The packaging I purchased was 1,000ml - enough for 3 uses and DOES NOT have a nozzle for pouring into the tank(!) - while with the same amount of money, you can get 5 packages of 300ml each!

Seems to do the job, probably not just for city driving. In 2 tanks, good "grip" on the highway and in between, at least one fill-up with enhanced diesel.