Update:I have now had this for about a month, and I have used it extensively. I have a 17inch neck and I have no problems with it going around. Don't be afraid if you have a thick neck but it's also small enough and tight enough that my wife, who has a much smaller neck could comfortably wear it gardening. Some people have complained and they cannot hear. Get your ears checked and cleaned. If it's been over two years, you waited too long. I usually use it on C-1 that's cooling with power one to the fan and it's quite enough for me to talk on the phone And use the ANC on my earbuds to talk on the phone as well. Most modern headsets now have ANC it controls the sound of noise around you which is very nice to have when you're someone like me who works at a desk and a very warm room and needs cool air to regulate my body temperature , I am still going with the belief that this would be a wonderful product for the elderly and I plan on getting one for my parents they can't hear anyway they're in their 80s and when they watch TV they use the close caption sound isn't really an issue. This is the best product that I have tried and tested so far. My favorite thing to do is to build giant scale airplanes in the garage. There is no air in my garage and it gets very hot during summer so this year I wore the new Coolify 2S. It allowed me to build with much more comfort than I have ever had.👍I wore this for about nine hours without using an external pack. I would have it on fan when I was inside a hanger and then I change to cool when I was outside, I did this all with the app. The best features for me was having the app on my phone and being able to plug in a light weight 10,000 mA back up battery when I use the back up battery I get about double the battery life so it has a good size battery in it. It's comfortable the case is awesome. I hooked onto the back up pack very easily. This is a thing of beauty that would help people in hospitals or hospice houses. We see so many patients who come down to the ER for heat stroke. Most of them are elderly when the first heat wave hit San Diego and the El Cajon and Lakeside areaThere was over 83 people in the ER. The whole bottom basement was filled. So it's a great tool to have keep you cool you drink lots cold water and you can go all day in the heat. I'm really looking forward to the airshow. This year I will get to go, and not worry about overheating. I'm a paraplegic cannot regulate my own body temperature have to constantly keep checking it so that I don't get too hot. I landed in the emergency room with heat stroke and the doctors were baffled. Lol.They pushed a bunch of fluids in me, five bags, and sent me home After I had fluid in me and I cooled off, and I felt better a lot better. While you're having a heat stroke, you won't make sense to the people around you. You're scared you don't know what's going on around you and you feel like everybody's out to get you. if you're over 60 and paralyzed get this product! It will change your outlook for going to dinner or lunch at a bistro outside enjoying San Diego restaurant, and also be cooling down.Joey