http://www.tradevv.com/chinasuppliers/dalisongen-ustradevv.comhttp://www.tradevv.com/chinasuppliers/dalisong/products-detail/china-MP3-earphone-2c9.html]]> 1.Sensitivity at 1KHz : 110+/-3 dB; 2.Impedance : 32+/-15% Ohm; 3.Speaker dia : ￠9.8mm; 4.Mylar : 6µ; 5.Frequency response : 230-12000Hz; 6.Input power : Nom2mw,Max4mw; 7.Distortion : Less than 5% at 1KHz 2mw; 8.Weight : Approx 23+/-3 grams; 9.connector : ￠3.5mm; 10.Cord length : 100cm/750cm; 2007-9-11 2:43:13