Headsets designed for gaming often feature a boom-mounted microphone so you can talk with other players during multiplayer gaming sessions. This feature is also ideal if you like taking phone calls while wearing headphones. Portable headphones designed for use with smartphones and MP3 players may include a small cord-mounted (or "in-line") microphone, along with controls for volume, mute and track advance. With wireless models, these controls and mics can be found on the earpiece itself, and many models are equipped with control functions that are optimized to work best with a specific operating system.