Super 6mm Dual Dynamic Drivers -- Use frequency division technology to pump out bright treble and deep bass respectively. It has ultra high voice resolution, which can better present the sweet or hoarse voice and other details Full bodied audio immersion -- Wider resolution and enhance the medium and high frequency output range. Tuned the ES2 drivers to not only sound great but also deliver long term audio output. Noise isolation and Ergonomic comfort design -- In-ear wearing with great flexibility and smooth solicone can isolate noise better. Perfect fit with 3 sizes of ear-buds that won't fall off. (XS/S/L size for your choice.)