I get confused while using it. It has a shorter shelf life than I thought about it. I couldn't maintain the heat for long and throughout since the battery dropped quite quickly. If I go out for more than 3 hours I almost can't use it more than 2 times if I don't turn it off and turn it on again when needed ... and an entire day is impossible .. .so when I first saw the amber car chager I bought right away ... in front of her eyes it will help me use ember travel mug 2 for a longer time. i hope the manual gets correct or wait for version 3