YUIN OK2 high fidelity earphones are different from the traditional earphones.with the fine workmanship,it can bring us special feelings on sound.You should own it. Transparent, smooth sound. Ultra low distortion, low impedance for high grade portable audio. Perfect for DVD scan CD,LP,MP3,multi media and so on. Earbuds / In-ear Earphone Convertible design (you can use the 3 set converters in the accessories to convert the modality of the earphones,very advanced, just as the picture shows). Specification Audio bandwidth :20Hz-20KHz. Rated impedance : 16 (4)ohms (at 1,000Hz). Sensitivity:108(3)dB(at 1,000Hz). Max input power : 500mV. Diameter : 3.5 mm. 6 feet Y cord. Package YUIN OK2 earphones 1/4\ stereo phone adapter plug Foam eartips ( 4 set for in-ear earphones,2 set for earbubs ) Storage box 3 set converters Carry Case