As in the previous comment, I fill it with very hot water I then mixed with water bottle to have good bottle temperature. As the contents of the thermos is enough to make 5 180 bottles heated through, for the day. Otherwise, I put hot water in the white cover and let soak the bottle (method recommended by the manual). It's quite long, I leave the bottle in advance. It takes a little space in the diaper bag, but thanks to the thermos, I was able to warm baby bottles in the train, WE in a hotel room, on the go, without fear ... not time find some way to heat and without charging me too much. I think this is the only baby bottle heater that allows this trip, others need a jack (or cigarette lighter) or must be recharged in boiling water after each bottle. Attention you can not put hot milk directly into it because it would quickly become a microbe nest, only warm water.
