This is a nifty little "activeequipment" brand, 17 Function Cycle Computer. It features a wireless speed sensor, wired cadence (RPM) sensor and allows you to analyse your cycling statistics in all manner of different ways.
Full details are available at http://direct.tesco.com/q/R.100-6555.aspx.
(Please note that it looks a little more modern than the photo on the website!)
The point of sale and tesco.com both indicate that this should be £15. But at my local Tesco (Cambridge), it rang in at a very tempting £3.75! That actually makes it cheaper than the 3-function Tesco Value model they also sell for around £6!
Grab yourself a bargain!