HiFiMAN Deva Open-Back Planar Magnetic Headphones with Bluetooth Attachment HIFIMAN is a company renowned for price-no-object, flagship electrostatic and premium planar magnetic circumoral headphones or even high-end IEM's - all wired. Now, HIFIMAN is also offering wireless headphones in the same spirit of pleasing the most demanding music enthusiasts. As a direct descendant of the Susvara and HIFIMAN’s other advanced planar magnetic headphones, the new DEVA PRO model features the company’s nano-thick diaphragm that delivers lightning-fast response, producing improved detail but ultra-low distortion as well. The frequency response is 20Hz-20kHz, sensitivity is 93.5dB, and impedance is 18 ohms. Acoustically Invisible Stealth Magnet Unlike the sound waves created by a conventional magnet, the special shape of Stealth Magets enable the waves to pass through the magnets without generating interference. HiFiMAN's advanced magnet design is acoustically transparent, dramatically reducing wave diffraction turbulence that degrades the integrity of the sound waves. The reduced distortion yields pure sonic output that is accurate and full-range. Bluetooth dongle The unique Bluetooth dongle turns DEVA into a powerful wireless headphone, supporting advanced high-resolution codecs such as Sony's LDAC and Qualcomm's aptX HD, making it well-suited to most currently available high-definition streaming devices. The dongle also adds the battery needed to support approximately four hours of playback per charge. This way, when users don't need the wireless transmission, they are not adding additional weight while enjoying the music. In addition to its wireless connectivity, the Bluetooth dongle can be used as a powerful integrated DAC/amp for smartphones and other low-power devices, simply by connecting a USB-C cable. A built-in amplifier module provides up to 1 watt per channel, and the two-channel high-fidelity DAC/filter ensures exceptionally detailed sonic output, no matter the source.