very easy to use. metered water depending on the amount of milk in the bottle and it will do the job. continuous LED: red (when it heats) and green (when finished) is clear and can not be missed, very useful in the middle of the night when you are asleep a half. and if one forgets it turns off a few seconds after the vaporization of the water. Avent baby bottles going well there. For small bottle careful it goes well heat up because the steam passes over!