The IE 900 from Sennheiser sets a new benchmark in portable audio fidelity through technical innovation (X3R), meticulous attention to detail, and an uncompromising demand for perfection. Every aspect of the IE 900 has been engineered to work in harmony to achieve the desired acoustic tuning and to reduce resonances and masking effects. Its acoustic design ensures brilliant, natural high-end sound reproduction and reveals even the finest details in the music