Simply explained this is the of width, rather than the diameter or depth of the wedding band and is measured in millimeters. We can supply a wide wedding ring up to 15mm in width if required

The width of the wedding band is very much a matter of personal taste you may prefer the delicacy of a narrow band, or the bold statement of wearing a wide band. However, generally speaking a delicate or small hand with slim fingers would better suit a narrower band, while larger, broader fingers would suit a wider ring.