the $ 39.99 -lrb- £ 26 -rrb- gadget is called the nanoheat wireless heated mug .
it keeps hot drinks at between 68 and 71 °c -lrb- 155 and 160 °f -rrb- for 45 minutes .
mug can be used more than seven times before it needs to be charged .
and it can be charged wirelessly or using a traditional usb cord .