2PCS Neck Cooling Tube with Cold Insulated Bag,Reusable Ice Neck Ring Wearable Body Cooling Products for Summer Heat (Blue)

This product is very effective, as long as you understand what it is and is not good for. The product uses phase change material (PCM). Like all PCM, it melts at a fixed temperature. It is not meant to be frozen. You can freeze it, but it won't stay cold for long. It will quickly warm to its melting temperature, and stay at that temperature until it melts. All PCM materials act this way. The only difference between them is that the melt temperature can vary. This product has PCM with a melting temperature of 82F. That means it is about 16 degrees below body temperature. It will feel cool to the touch, but not cold. It is most effective when you are doing something that makes you warm, like working outdoors in the heat. I use mine when I'm working out at the gym (no A/C) and it is VERY helpful there. It's like having a damp cloth on my neck, except it doesn't drip, it doesn't get soggy, and it doesn't matter if it's humid. The big advantages of this particular PCM product are: - It takes a long time to melt, 2-3 hours in my experience. - It resolidifies quickly at room temperature. It goes faster in the fridge or freezer, but that is not required. - It stays solid at room temperature (as long as it's under 82F) which means you can store it, ready to go, without keeping it in the fridge. There are other similar PCM neck rings on Amazon that have lower melting temperatures (64F is common). Those products will feel colder and provide more cooling. HOWEVER, they will also melt faster (~20-30 minutes) and will have to be kept in the fridge to be ready to use.