Soft rubber caps. Pump up the bass. Made for MP3, CD, iPod, iPhone. 1. Pump up the bass - with tiny, extra-high quality speakers that deliver rich, deep bass and crystal clear sound. 1. Integrated cable relief with non-slip grip - the strength to withstand pulling and stretching, non-slip grip also for easy fit into ears. 3. Long-lasting comfort - thanks to extra-soft hybrid silicon caps and soft outer sleeves. 3 sizes of rubber caps. 3.5mm gold-plated plug. 3.9 feet cable length. Symmetrical. Cable slider. 10 - 23,500 Hz frequency range. 100 dB sensitivity. 16 Ohm impedance. 15 mW maximum power input. Made in China.