Luxury wireless headphones with microphone and controller. With the most modern Bluetooth hardware and software, integrated aptX codec technology, the BT540i headphones are the most advanced Koss Bluetooth headphones. Built-in dual microphones work in sync for background noise reduction and exceptional call clarity. The built-in controller allows you to quickly play and pause songs, adjust the volume and answer incoming calls. The headphones are equipped with completely new, precisely tuned, dynamic Koss PLX40 elements, which are characterized by sharp treble, strong middle and full bass. The premium leather memory foam ear cushions completely cover the ears and perfectly isolate the surrounding noise. The built-in lithium-ion battery provides more than 12 hours of listening time on a single charge. Detachable audio cable included for use in case of low battery. The headphones can be easily folded. Accessories include a practical carrying bag, a USB charging cable, an analog charging cable with a 3.5 mm jack connector, which can be connected after the battery is discharged and can still be used.

Specifications:
- Frequency range: 10 Hz - 25000 Hz
- Impedance: 38 ohms
- Sensitivity: 100 dB SPL.