One of my favourite biohacks that I use regularly is a simple device called NuCalm.
Author, coach, speaker, and philanthropist, Tony Robbins in his new book Life Force

Tony Robbins loves NuCalm. He has dedicated his life to helping people perform and live at their highest level and has put out to the world an extraordinary amount of energy.
It’s no secret that Tony is an avid user of NuCalm, an avid user and major contributor of Ignite Warrior Brain, and an avid user of DEEP SLEEP. Tony is what we would call a ‘power user’ and he has been a voice inside the NuCalm neuro acoustic software journeys and a larger voice to the world. If you would like to purchase his book, click here.