For its cost, unexpectedly good. Time will tell regarding its durability. What I didn't see mentioned is that it essentially functions as a "hand warmer," which is why one side has extra material that acts as a pocket for the hands

You plug it in, it stops when the water inside gets hot, it’s a fluffy gray nice fabric, it only heats one side, I gave it as a gift to my mother for her back, it relieves her a lot. You can also use it on your hand or your foot if your wrist or ankle hurts. I don’t have an opinion on its durability, I ordered it and we’ve had it for 1 week, it heats up quickly and lasts about an hour

Heats up fully in 15 minutes.
The heat lasts for an hour and. (heat that warms you fully, then it starts to drop.)
Smells a bit like plastic-Chinese, but bearable.
Its interior is like a pouch so you can wrap it around your arm/leg to warm it up. The back side definitely gets hotter than the front.
For 7 euros, quite satisfied.
(given that hot water bottles of the same size cost 10+15 euros at pharmacies and are not electric, so you have the hassle of boiling water etc. and they don't last as long)

Perfect. You don't need to keep it plugged in all the time. You heat it up in the socket for about 5 minutes, and it stays hot for 30.

I haven't used anything similar, however, this specific one heats up quickly at first and burns you. I found it to be very hot water, I would say boiling, and you forget how many hours it emits heat; I gradually reduce it, but it doesn't stop emitting. I found it small, impressive, and made of very beautiful material. It does its job and more than that. I would buy it again