Sorry...I am not using one; they are too expensive for my budget. (I'm 82 years old; 4 years post Covid and on Social Security)
But, I thought to add this tidbit: When I take my shower, I turn on the cold water at the very end and with my handheld showerhead, I put the cold water on both sides of my neck. It works to stimulate my vagus nerve and I'm usually feeling 'normal' (good) for about 2 hours allowing me to get out and do an errand or two. My best to you.