2.5mm stereo plug to 3.5mm mono jack adapter 2.5mm stereo plug to 3.5mm mono jack converts 3.5mm mono plug to a 2.5mm stereo plug.The adapter is assambled of black molded plastic with nickel-plated contacts.Black molded plastic construction nickel-plated contacts connector 1: 2.5mm stereo plug connector 2: 3.5mm mono jack external length / height: 37mm body diameter: 10mm