Choose your favourite: widths of4mm, 6mm, or 8mm andlengths of 16", 18", 20", or 22" —ideal for layering or wearing solo. Curb Chain Necklace. - Widths: 4mm, 6mm, 8mm. Whether you’re dressing up or going casual, this versatile chain adds a bold touch to any outfit and makes a great gift for any man.