The Suzuki Overdrive is the most radical new harmonica design in years. It has no aperture in the back, but holes on the top and bottom cover plates let the air in and out. The comb is solid plastic (most plastic combs are chambered) and each reed is partitioned individually to increase airtightness. This help generates a thicker tone and excellent volume. If you play using the overblow technique, closing off the holes with palm or fingers facilitates the overblow or draw.