I take off a star because:
- It takes some time to warm (the time the water boils + the time the kettle will "recharge"). When you have a stomach ache, it's not always easy to wait 15 minutes!
- Over time, the limestone builds up on the kettle (but that hand if you place your hand on it, and it's not so bad) and crystallization does not occur in the same way, then it is no longer "pretty" as in the beginning! I have the impression that they also heat up a little less time, so it was not an infinite lifespan.
Tips: When you turn the kettle, you have to watch that ALL crystals have melted the kettle! And do not try to reactivate the kettle while it is still hot, it will not work ... When cool water bottle, you should have no problem activating it, even if you do not bend the pellet around!