Portable Bottle Warmer for Travel – Moclever USB Rechargeable Baby Milk Warmer, Battery-Powered Breastmilk Heater On The Go, 6 Adjustable Heating Levels, Digital Display, Fits Most Bottles

Very simple as it's basically strapping heating strips around a bottle and sticking an power bank on top. It does work but takes a bit of time, which I found that if you swirl it a bit, itll heat a bit faster. Great for travels/ outdoors when you can't get to anything else.

This is my second warmer of this type. The first one was a different brand and it was terrible. Only the bottom plate heated up and it failed to warm up the milk after a full hour went by. I gave up on this type of warmer, but decided to give this one a try again. This works much better than the other one, but can still take some time.Unlike my previous one, the fabric wrap heats up. This provides much more surface area than just heating up the bottom. When used with my narrow Dr. Brown's bottle, it provides good contact to all 8 oz of milk.The device heats up quite a bit, but it still takes quite some time to warm up refrigerated milk. It took about 30 minutes to get the milk to what I would consider a lukewarm level. The device tries to measure the temperature (in Celsius). I'm not sure how accurate this measure is, as the temp probe is only at the bottom of the bottom. At a reading of 30C, it was at the appropriate milk temp.If you plan to use this, give yourself several minutes to let the milk heat up.