This is such a time and life saver. Especially at 2 or 3am in the morning. I prefill my bottles with formula powder then pop them in the machine when needed. So this does a hit of hot water, you still have to shake the bottle then it does a hit of cold water and you shake again. No measuring or really thinking required. Perfect temp everytime. I would buy this over and over again. I love it so much! Great gift for anyone who formula feeds!