It's a synthetic blend media, ie., synthetic fibers and cellulose media. Used to give that information on the Bosch website also including an up to 15k mi fci recommendation. It is most comparable to Mobil 1 oil filter.
The Bosch website used to give more information when the BD+ was first introduced, but now it's much less comprehensive. Same goes for much of the other filters information there too. Not sure of reason but no longer being a part Purolator owner might be a reason, but that's just speculation on my part.