They work well Several freinds had them and all of them loved them It looks like that one has been in a fire, does it come with a warrenty I have a brand new one in the box that I have never treid, as soon as I bought it VDO came out with thier Extreme playback tach,so I bought it also It works very well One of the benefit of a playback tach that records the entire run is you can see the RPM drop back on each shift so you can see what the converters does better instead of trying to look at the tach for that, the VDO playback will play back in 1/3 real time or at real time, your choice