In the package, it says that it lasts about 12 hours. Its duration was 9.5 hours, but I have no complaint. It is prohibited to stick it directly to the skin, so I stuck it on my shirt and with a blouse and a jacket, it kept my waist warm for five hours in the rain and in the air.

On the positive side, it does not contain dangerous chemicals and when it cools down, it can be disposed of in household waste.

On the negative side, it is palm-sized, so depending on the size, height, and level of warmth needed, corresponding patches will be required. I don't know if it could be a permanent solution for someone who works permanently outdoors due to the monthly cost. It definitely benefits someone who goes on occasional motorcycle trips, a snow trip, etc. However, whoever chooses it will be kept warm.