From what we have observed, non-dyed (natural) Type III anodic coatings usually provide the maximum degree of wear and abrasion resistance. However, matching colors from non-dyed Type III coatings can only be achieved by a well controlled and calibrated anodizing process AND at a great cost. This is especially true with 6061 type materials. It's much easier to obtain consistent results with 3000 series materials such as those used in Calphalon cookware. You'll almost always need a huge anodizing tank and temperature about -3 to -6 degree Celsius maintained throughout the process to begin with. Very few such facilities exist in China, and almost none exist in southern part of China where most Chinese flashlight manufactures are based. It's also very difficult to do it right in southern part of the US especially during the summer.
While black colored Type III coatings are not necessary inferior to the non-dyed Type III coatings, the color can sometimes coverup the substandard coatings. Some manufactures even use colors that look like non-dyed coatings.
I won't get into the details of how we managed to obtain that thick, dark, and color matched natural Type III coatings.
