Haven't seen this one before but it looks like so many of this type of add on box that changes signals going to the ECU which then fools the it into changing (usually increasing) the fuelling. Some of these boxes are nothing more than a variable resistor costing a few pence in a fancy box. For a little bit more money (£100?) you should be able to pick up a S/H Power Commander which will do a much better job. It all depends what you're trying to do with your Vee?