These earbuds connect to the sound source via Bluetooth and pair together for true stereo sound. They have large 10mm drivers for exceptional sound fidelity and clarity. They are rechargeable and come with a charging base, including battery pack, that can charge the earbuds three times per charge. Excellent quality, Bluetooth 5, you can use either of them as single/master for music and phone use. each bud contains 2 mics, providing noise cancellation. Bought as a birthday present, we are sure these earpieces will be well-used and loved.