C.P.
I have personally tried two different "bottle" warmers for the car and did not like either. They took atleast 20-30 minutes to warm up. Yes it is so much easier to take frozen or chilled breastmilk and bottle feed in the car, so I finally learned. I got one of those travel coffee mugs that plugs into the adapter to keep warm and it works AWESOME. It takes just as much time to warm a bottle in one of those as it would at home. Those are easiest to find around this time of year too, so good luck and hope this helps.