"To the left, to the left" on the left and right

the audio played on the left is different than the audio played on the right. each side says 10 different letters and number, the video tells you which one to listen to at that time.

And the letters use the NATO Phonetic Alphabet.

https://www.youtube.com/watch?v=B8VJ4FVDUuk

but fr,

Autonomous sensory meridian response (ASMR) is an experience characterized by a static-like or tingling sensation on the skin that typically begins on the scalp and moves down the back of the neck and upper spine. It has been compared with auditory-tactile synesthesia. Autonomous sensory meridian response (ASMR) signifies the subjective experience of 'low-grade euphoria' characterized by 'a combination of positive feelings, and a distinct static-like tingling sensation on the skin'. It is most commonly triggered by specific acoustic, visual and digital media stimuli, and less commonly by intentional attentional control.

https://www.youtube.com/watch?v=b1EXJoIntlk