... ) Oxygen free copper and Tangle-free cable. *Specification1) Earpieces are Aluminum & Natural Wood2) Frequency response: 20Hz-20 KHz3) Impedance: 16Ω±15 ... : 99-108dB6) Rated Input power: 3mW7) Wire: PU/PVC/Silver Aluminum foil line, length 1.3M, diameter 1.8/2.0mm8) Plug ... , Nickel/Gold-Plated9) Net Weight: 16g *Color Optional No.6063 aluminum housing parts, 9 colors available below: