This thermal bag is fantastic, it fits most bottles (as I've used a couple of different ones such as Avent and Medela). It keeps the bottle nice and warm for a reasonable amount of time and it also keeps it snug. I like that it has the velcro loop and snap tag/hook so that you can attach it to your nappy bag or the pram. This has been handy when there's no more room in the bag.
Keeps the bottle warm, reliable and inexpensive in compared to others. Also has the velcro loop handle and hook to attach to bag or pram if needed