Review (5/5): It works well.
I didn’t use the bottle it came with. Instead I use the bottle my oil was already in and it works. It takes time for the oil to warm up, but I think it’s because the circumference of the bottle that I have it in isn’t big enough to touch the warmer itself. But it still warms it up and it can be in there all day and it won’t heat up the oil to be hot, only warm.