The Driver Unit is the powerhouse inside your headphones, creating the sound like miniature speakers. They are measured in millimeters and in general, the bigger the driver, the greater the capacity for sound creation and deeper bass reproduction. That’s why the 50mm drivers of Sony eXtra Bass headphones have such impact.
However, fitting large drivers into compact headphones like in-ear models presents a challenge. Sony has overcome the problem with the extraordinary EX Monitor premium model, which packs in a 16mm driver for an ultra-wide dynamic range; delivering high-fidelity treble and the deepest bass ever achieved in an in-ear headphone.