It's a clear liquid (so it's definitely not adding color) that works on vinyl/rubber and gets them darker/shinier but doesn't seem to last very long and needs to applied regularly (as the instructions state). The instructions state that it is activated by the sunlight so I guess UV protection is not included.
Also, "Black Again" SHOULDN'T be used if you're really close to repainting your exterior vinyl (oxidation/stains) as it add a type of oil coating to your trim.
I bought a bottle and have been using it regularly as a treament on my black trim and mostly my tires. It gives a nice sheen but if your material is oxidized badly it won't do anything. If your trim is in fairly good shape it seems to work. I tried it on my '97 Honda and it helped somewhat.
I will try Forever Black next time for treating the more oxidized areas.
2004 E60 530is, Delivered 12/12/03, TiSilver/LGrey, PP, SP,PS, PDC, ACC, FRS, Step, Xenons, clear bra, body colored rear inserts. (Retired, 1983 henna red 320is)
2004 Corvette Z06 Commemorative Edition