What are "DiMarzio^® black back pickups"?

Although "black back" is not a nickname that we have ever used, it commonly refers to the fact that some of our humbuckers have black base plates rather than brass or nickel silver. This is simply a cosmetic choice which does not affect performance, and it doesn't actually refer to specific models. However, the Breed™ and Evolution^® models are built with black base plates as a standard feature.