At one end of Lindy's Universal Mains Plug & USB Adapter is a female connector that can take UK three-pin, American two-pin, European round two-pin and Australian at-an-angle plugs.
At the other end, you can switch between EU, UK, Australian and US pins. Plus, you can remove the cap and replace it with one that offers a single USB port, for powering or charging devices that use USB in this way.
The device is small enough to carry around in your bag, and replaces a whole slew of plugs and adaptors.
It's designed for use in Europe, UK, Hong Kong, Singapore, USA, Canada, Japan, Taiwan, China, Australia and New Zealand, and has a power rating of 110V-550W/5A and 240V-1200W/5A, with an internal fuse that trips at 2.5A.
Remember, it's designed to change the shape of the plug, not the voltage of the power supply, so make sure your device is designed for use in the country you're in.