Bruno Tilz 305-T 2 vs Bruno Tilz 306-5 GS
The Bruno Tilz 306-5 GS has a wider cup diameter, the Bruno Tilz 305-T 2 features a deeper cup, the Bruno Tilz 306-5 GS has a larger throat opening.
Cup Diameter
The Bruno Tilz 306-5 GS has a cup diameter of 26.00 mm / 1.0236 in compared to 25.00 mm / 0.9843 in on the Bruno Tilz 305-T 2 — a difference of 1.00 mm / 0.0394 in. A wider cup generally produces a fuller, darker tone but requires more air support.
Cup Depth
The Bruno Tilz 305-T 2 has a deep cup while the Bruno Tilz 306-5 GS has a medium cup. Deeper cups favor a darker, richer sound; shallower cups provide more brightness and easier upper register.
Throat Diameter
The Bruno Tilz 306-5 GS has a wider throat (6.80 mm / 0.2677 in vs 5.40 mm / 0.2126 in). A wider throat allows more air through, increasing volume and projection but reducing resistance.
Which is better?
Both mouthpieces are categorized as "Catalog" — the physical dimensions above will determine which suits your embouchure and playing style better.