Litle thing. Cost just over $80.
Have not set the screens or readouts yet but first and only test showed the CAT temperatures. given more tme I will set it up to show that, voltage, turbo boost, torque, horsepower and fuel pressure on the same screen.
You can read trouble codes and clear them as you would with a scanner. It also deals with fuel conumption timing, fuel pressure and a number of performance options.
Have not mounted or really tested it yet but did just set it on the dash in front of the speedo and used one of the generic screen options.
Also noted in the information that it can read out particulate filter status. Might be very informative to know when a regeneration is coming and watch the temperatures in the CAT as it happens.