The hf2 is a high-fidelity, hands-free noise-isolating headset and earphones combination. Made to work with your Android, Blackberry, iPhone or other smart phone. But it's really much, much more than that. The hf2 provides a near-perfect music experience. Made by Etymotic Research, the people who created in-ear earphones, the hf2 delivers Etymotic's world-renowned sound quality in a comfortable, convenient wireless phone headset, so you'll never miss a call! Headset includes a high-sensitivity microphone and a Music/Call button that allows you to quickly answer calls while controlling your music. You'll be able to hear and be heard, clearly, even in a noisy environment. The hf2 includes the in-ear headset and earphones, assorted eartips so you can find the ones that fit you best, carry pouch and filter changing tool with filters. Compatible with iPhones and most music players (e.g., iPod, mp3, CD) that accept a 3.5 mm stereo plug. The hf2 cable slider can be adjusted by moving it up or down for a snug fit. And now, available for the hf2, you can download the AWARENESS! for Etymotic app from iTunes. AWARENESS! for Etymotic is an innovative earphone app for anyone who uses an Etymotic hf3, hf2, mc3. mc2 or ETY-Kids headset or Etymotic earphones and needs to hear sounds around them. AWARENESS! for Etymotic listens to your surroundings while you listen to music. Any sound louder than normal background noise can be heard in your earphones. It's not just a stand alone app. AWARENESS! for Etymotic runs in the background and monitors sound while music and media players, audiobooks and games are in use. Once you receive your earphones, to use AWARENESS! for Etymotic, follow these steps: 1. Download the AWARENESS! for Etymotic app from the iTunes App Store. 2. Register at Etymotic's website (etymotic.com/awareness) to unlock all features. 3. Enter the code emailed to you in the AWARENESS! for Etymotic App. And enjoy your music safely!