I have a Garmin that uses the ecoleaf (I think thats what it's called) Bluetooth unit that connects directly to the ODBII connector and connects through Bluetooth to the Garmin unit. it pulls telemetry from computer, and has multiple gauges that you can display at once on the screen. since my touring was from Merca, the speedo was in MPH, and since I'm in the land of the Canadian Cobra Chicken, I needed a speedo in metric, so on the Garmin, I show speed in KMH, RPM, Coolant temp, Voltage, and engine load in %, you can only have 5 at time on display, but there are other options to display as well, such as air intake temp, and a couple of others don't really use. works well, but there are only a few older Garmin models that use the Bluetooth module, so sometimes you have to go hunting for the units.