In-the-ear design fits snugly yet comfortably allows you to enjoy music during active movement. The closed-type earplugs design reduces outside noise for high-intensity listening; generating a powerful resonant bass response akind to a sound-proof environment ! New miniature 9 mm drivers are a key enabling technology; producing powerful sound with space left over for the sonic isolation of Sony's silicon earbuds which reduce outside noise provide long-lasting comfort hour after hour. They are washable removable and replaceable and the supplied three sizes of earbuds (S/M/L) accommodating a full range of ears. 400 kJ/m Neodymium magnet embedded for maximum energy in minimum size; ounce for ounce. Even with the small 9 mm drivers Neodymium achieves 100 dB of sound pressure output from a modest 1 mW input power. Streamlined compact case neatly stores the ear-buds and headphone cord with vivid purple styling. It's also high-impact ideal for carrying in a pocket or backpack while minimising cord tangles; partial winding can shorten the effective cord length during use. Specifications : Lateral In-the-ear Closed Dynamic Earplug System 9mm Aperture (CCAW voice coil adoption) Drivers OFC; Neck Chain 0.5m (remote friendly) Cord Gold-plated Stereo straight mini plug 16 ohms at 1 kHz impedance 100 dB/mW sensitivity 100mW Power handling capacity 6~23 000Hz Frequency Response