Specifically designed with cellular talking microphone on/off function or MP3 player with 3.5mm earphone jack. This Bullet Headset integrated voice functionality gives you the freedom of hands-free phone calls or enjoy in ear music. This versatile set of earbuds is perfect for all MP3 player and cell phone with 3.5mm earphone jack users - it features durable bullet heads, a built-in microphone with power off/on button, and a shirt clip for comfort and ease of use. The mic button also doubles as a music control, needing two clicks to display your tunes. The Glossy Bullet Headset use the same speaker technology and sound signature used in professional monitors. Their noise-isolating in ear design sits inside your ear canal to create a seal to the outside world that effectively isolates outside sound. So it"s just you and your music in a world of your own.