Firstly, Thomann's translation is rubbish. For your knowledge, "Inner drum shell" refers to inner rim diameter and elsewhere "drum" refers to the space in the cup. This particular cup is very big and shows less immediate response than its (weird) Model 13 brother. Consider the two related only in rim size and contour. In this extreme, BIGGER does not always mean BETTER. I don't like it, but you might. No rim is better than Engelbert Schmid's, and many mouthpieces cost much more.