Headphones are a pair of small loudspeakers that are designed to be held in place close to a user's ears. Headphones either have wires for connection to a signal source such as an audio amplifier, radio, CD player, portable media player or mobile phone, or have a wireless receiver, which is used to pick up signal without using a cable. They are sometimes known as earspeakers or, colloquially, cans. The in-ear versions are also known as earphones or earbuds. In the context of telecommunication, a headset is a combination of headphone and microphone.