Help finding kw meter

[Abyss]

I'm trying to find a device that can be plugged inline into a plug socket to see how many Kw/hrs a device is using. Any ideas what they are called? I've googled and searched ebay to no avail

 

[basmic]

I shall point you here and here.

I've just bought one - I am eagerly awaiting it's arrival.

 

[Abyss]

Cheers