The car is washed, the paint is clean, and it still looks unfinished. The tyre sidewalls are grey and brown. A glossy spray off the shelf lights them up wet for a while, but after the first drive you'll find it slung across the sills and behind the wheels, and within two weeks the rubber is grey again.
The browning isn't dirt. Rubber contains a protective additive that slowly migrates from the depth to the surface, where it browns on contact with air. Heat and driving speed that up. A dressing built on solvent and silicone leaches that additive out of the rubber and leaves a tacky film on the sidewall that binds dust. The rubber then browns faster. Our article on why tyres brown explains it in detail.
FEYNLAB® Black Velvet is for you if you want the sidewalls black between washes too, and it bothers you that within two weeks it looks like before again. If it's enough for you that the sidewalls are clean and matte black straight after a wash, a hand exterior wash is all you need. If you'd rather not renew the treatment and want peace from your tyres for the whole season, reach for ceramic tyre protection.