retractable earphone, 1.Support mp3/mp4/mobile phone. 2.The best price & High quality. 3.Eco-friendly products. retractable earphone, 1.Abundant supply.2. Fancy and exquisite design.3.Frequency Response:: 20-20kHZ Driver diameter : Φ40mm Mylar thickness:19u Normal Power: 5mw MAX Power: 15mw Sensitivity: 115+/-3dB Impedance: 32Ω+/-20% Cable Length : 1500+/-50mm Plug: Φ3.5mm(Stereo)4.Packing ...