A headset combines a headphone with a microphone. Headsets are made with either a single-earpiece (mono) or a double-earpiece (mono to both ears or stereo). Headsets provide the equivalent functionality of a telephone handset but with hands-free operation. They have many uses including in call centers and other telephone-intensive jobs and for anybody wishing to have both hands free during a telephone conversation.

Headsets are available in single-earpiece and double-earpiece designs. Single-earpiece headsets are known as monaural headsets. Double-earpiece headsets may support stereo sound (two slightly different channels of audio signal, one for each earpiece), or use the same audio channel for both ear-pieces.

Monaural headsets free up one ear, allowing interaction with others and awareness of surroundings. Telephone headsets are monaural, even for double-earpiece designs, because telephone offers only single-channel input and output.

For computer or other audio applications, where the sources offer two-channel output, stereo headsets are the norm; use of a headset instead of headphones allows use for communications (usually monaural) in addition to listening to stereo sources. Telephone headsets generally use 150-ohm loudspeakers with a narrower frequency range than those also used for entertainment. Stereo computer headsets, on the other hand, use 32-ohm speakers with a broader frequency range.

Source: Headset (audio) from Wikipedia

This Icon is available to order as a Decal or on a T-Shirt