The STAX SR-L500 MKII is an electrostatic earspeaker with an exchangeable cable mechanism in case you want to upgrade to a high-definition cable and a case holder made of aluminum that increases wearing comfort when listening to music. 

The SR-L500 is equipped with a thin-film diaphragm and tough stainless fixed electrodes for a rich deep bass, delicate high frequency, and a soothing mid-range. The headband comes with a slider mechanism that can be adjusted for comfort and long listening sessions. 

Specs:

• Fixed Electrode: High precision etched electrode
• Attached Cable Conductor: HiFC*
• Ear Pad: Artificial Leather (skin touching portion and surrounding portion)
  
• Weight: 351g, 479g (including cable)
  
• Type: Push-Pull electrostatic sound element, open-air type enclosure
  
• Sound Element Shape: Oval
  
• Frequency Response: 7Hz - 41kHz
  
• Electrostatic Capacitance: 110pF
  
• Impedance: 145k ohms
  
• Sound Pressure Sensitivity: 101dB
  
• Bias Voltage: 580V DC
  
• Cable Type: Parallel 6-strand, low-capacity wide cable
• Cable Length: 2.5m