3.5mm Mono Plug to 6.35mm Mono Jack Adapter. 3.5mm Mono Plug to 6.35mm Mono Jack converts 6.35mm Mono Plug to a 3.5mm Mono plug. The adapter is assambled of black molded plastic with nickel-plated contacts. Black molded plastic construction. Nickel-plated contacts. Connector 1: 3.5mm Mono Plug. Connector 2: 6.35mm Mono Jack. External Length / Height: 52.3mm. Body Diameter: 12.7mm.