I bought this bottle warmer, because I thought to heat up baby bottles so quickly and easily. This is not like that. Bottle of water pure, pure, press button - While the actual use of the NUK Thermo Rapid is simple. But that was about it. Filling by means of water is a fiddly affair until you have specified in the manual amount of milliliters of water in the measuring unit in it. Thus the "right" amount you have - at least mentions the NUK in the instructions - you have to actually have the manual always at hand, unless you memorize or are always a lot. Then comes the next phenomenon - either the bottle is hot and the contents cold or hot contents and the bottle cold. We have NUK bottles and other manufacturers that does not really matter. So we now have a bottled thermometer fetched. If the milk bottle was not sealed or drops ran down: the cleaning of the device is also not so easy.