The 3.5mm connector is commonly called a 1/8-inch connector or a mini-plug. It is a small, thin metal plug that can be used to carry one, two, or even three signals. The tip of the plug is separated from the sleeve of the connector by a concentric band of insulating material. For stereo or audio/video versions of the plug, there may be one or two additional metal bands, called rings, placed between the tip and the sleeve. 3.5mm connectors are commonly used for computers and portable devices. A computer’s sound card uses these connectors for speakers, line-in/line-out connections, and also for microphones. Portable devices use the 3.5mm interface as a line-out connection for headphones or for connection to an auxiliary input on an amplifier. The “three-pole” version of the 3.5mm plug is often used on camcorders. This plug has a tip and two rings, which can carry video as well as right/left stereo audio.