Initially encouraged but
This has gone back to Halfords. If you have it delivered to one store it needs to be returned to that store. First big mistake!
The device I received seemed well made, the data was easy to read, the device that locks it in place on the stem worked very well. The accuracy of the device was extremely poor. More so it was not consistent. Initially I suspected something was wrong when going at very low speeds, less than walking speed it showed 18 mph. I first though it read 1.8 mph... so more extensive tests. At times free wheeling down very steep hills, a GPS app indicated circa 30 mph, the VDO suggested otherwise, 10 mph. There are times it is accurate but at others it is very wide of the mark, I don't know about these things from a tech point of view, therefore I would suggest a software problem :) The build quality is very good, but the device is not consistent in providing accurate data so the value rating is unsatisfactory. The device was wired and installed according to the manufacturers instructions.
Verified purchase: YesCondition: New