TRULY WIRELESS: Compatible with Apple or Android cell phones, sync using Bluetooth connection & NFC DIGITAL NOISE CANCELING: WF-SP700N headphone set minimizes distractions & noises for crisp listening AMBIENT SOUND MODE: Blend music & environmental sounds during fitness sessions or outdoor workouts SPLASHPROOF: IPX4 rated to handle sweat or rain splashes when you're at the gym or outside running LONG BATTERY: SP700N has up to 9 hours of playback battery life during workouts or athletic training