Top Class built-in lithium batteries support up to 48 hours of talk/music time. Designed for your active lifestyle. These earplugs are IPX 5 and can withstand sweating. Wireless earbuds with Bluetooth A2DP technology and microphone, providing you with high-quality pure stereo audio output with rich bass, clear midrange, balanced treble, and high definition. High-grade Mic allows you to take calls with the same quality as with your phone. Ultra-lightweight earbuds with a 45Â° oblique angle, flexible neckband with streamlined design, allowing for ultimate wearing comfort to match your active lifestyle like workouts, commute, running, jogging, cycling, driving, camping, hiking, gym exercise, and other outdoor sports. Built-in magnets allow you to connect two Bluetooth headphones together when not in use, helping you pack easily and avoid loss. When you don't use wireless earbuds, the earplugs can stick to each other, it will hang around your neck, wear like a necklace around you, and it's a convenient way to carry it when you don't need it.