Sony MDRXB60EX 13.5mm Driver Extra Bass In-Ear Headphones (Gold) (Discontinued by Manufacturer) 13.5mm driver units for deep, powerful bass (4-25Hz) Advanced Direct vibe structure for enhanced performance Optimized housing design for ultimate wearing comfort Hybrid Silicone Ear buds. In 4 sizes, for a personal fit Noise isolation ear buds, 3 sizes, for increased noise attenuation