C&E 3.5mm Flat Audio Cable Black 3 Feet, CNE594453 It is 3.3mm long and 5.7mm in diameter, which is long and thin enough to allow for a good connection through almost any protective case. This cable features a flat cord design that measures 3.5mm wide and 1.5mm thick. The connectors are gold plated for smooth, corrosion-free connections. Flat cable design resists tangling. Gold plated connectors.