Monaural Beats 40 HZ Sawtooth.mp3 played on Portable Mini USB FM Radio Speaker Music Player

Monaural Beats 40 HZ Sawtooth.mp3 played on Portable Mini USB FM Radio Speaker Music Player
I am starting to use this $14 gadget to play the audio file:
https://youtu.be/f2XU8d6ydbw

Portable Mini USB FM Radio Speaker Music Player $14: https://www.amazon.com/gp/product/B00KCIW7KG/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&th=1
Exact 40 Hz Gamma Brainwave audio used by MIT to prevent Alzheimer’s.mp3 - https://drive.google.com/file/d/16cAxDy8KM8zQB7Xf9Dl7VKQ48Jk6hgBx/view?usp=share_link
Monaural Beats 40 HZ Sawtooth.mp3 (I created this MP3. It has not been validated in studies) - https://drive.google.com/file/d/1RdUlpuwve7ZBbH1GX7tHIcArFS1IbCVN/view?usp=share_link