Seen loads at my local store in Glasgow. Not bad for a tenner, seen many on ebay for around £20+.
This is the extension cable which you unwind, its wound in a circular 'thingy' and it has 4 connections. Ideal for garden work or using electrical devices in a distance from your house/property.
25 metres, 13A, 4 connections.
Note: picture is for illustration purposes only, the one I am talking about is the same concept but it has 4 sockets.