If you've ever needed some motivation to turn lights off when you leave a room then here it is: the stern but kindly face of Optimus Prime to remind you that Energon is too valuable to waste.

The generation-spanning Transformers series has grown to a global household name. The war between the Autobots and the Decepticons rages on, as they battle it out for control of their worlds.

This ceramic mug has a capacity of 315ml / 10oz and is dishwasher and microwave safe. Presented in a secure box, this mug is a great gift idea.