KAOLALI 52mm Digital GPS Speedometer - LCD Speed Gauge Odometer with Adjustable Mileage & Trip Counter - Universal 9-32V GPS Antenna for Car, Motorcycle, Truck, Boat (Silver) - Perfect for Off-Road, Racing & Marine Navigation

I have no trip odometer in my van and my gas gauges are suspect at best. I was tired of writing down my mileage to make sure I didn't run out of gas. As long as I remember to press the reset button I can easily see my elapsed mileage. It seems to be fairly accurate for monitoring fuel per each fill up but I use the van's odometer for actual mpg as they differ slightly. I mounted the reset button near my tank selector ( I have two tanks) so I remember to reset. It works for other gauges as well but I do not need those. The speedometer is a nice bonus as well.