It works just fine and lasts about 20 minutes. Ideal for heatwave days if you are outside for some reason. It will buy you a little time before heatstroke!

6.4.24 update.
Previously, I had written that it doesn't work,
but in the end, it does.
It just doesn't want you to break it with your hand, meaning to press it slowly until it breaks like I did.
It wants slaps. Hold it in one hand and slap it with the other. Don't worry, it won't explode or puncture.
It wants its slaps. Hit it hard and it cools down.
The damn thing is actually good