Features: Drive Unit (diam. in mm): 9.0
Impedance (Ohm) / 1 kHz: 16.0
Sensitivity (dB / mW): 97.0
Max Input (mW): 200.0
Frequency Response (Hz - kHz) (en JP): 10Hz - 24kHz
Cord Length (m: 1.1m
Weight (g) without cord: 4.0
MiniPlug 3.5mm: yes
Plug Type (en JP): Nickel Plated
Magnet Type (en JP): Neodymium
Colour (en JP): Black

http://www.panasonic.com/uk/consumer/headphones/in-ear-and-clip/rp-hje125e.html