The DSR9BT is the first audio-technica headphone to introduce the Pure Digital Drive™ technology. This technology doesn't work like most on the market, and could quite easily set the benchmark for premium headphones going forward.
In essence the signal is communicated via Bluetooth but stays in digital format right up until it hits the driver. The driver then converts this signal straight into audible energy. This removes the need for a DAC (digital to analogue converter) and additional hardware getting between the source and the listener. The result? Less distortion/ colouration and more clarity/ transparency.