Clear Call and Immersive Stereo: Side sleepers earbuds have strong 13mm speakers driving units and in ear acoustic structure support, which produces a strong bass, clear mid sound, and bright treble. The unique acoustic design of the cavity room, balanced internal and external air pressure, avoid sound loss, ensure stable sound and penetrating power, even in a noisy environment can provide clear voice detection. You can enjoy your personal space whether you are indoors, outdoor, work or exercise