Sennheiser CX 300-II Precision In-Ear Earbuds / Earphones Offering a powerful, bass-driven stereo sound with greater clarity and improved dynamics. The various sizes of ear adapters (S/M/L sizes) provided in the package allow for a personalized fit as well as a high passive attenuation of ambient noise.  Also, the asymmetrical cable design ensures a high wearing comfort as you listen on the go.