I haven't gotten around to installing this in my boat, but I have bench-tested one of these hooked to a fuel gauge from an early 90s Prostar. Seems to work just fine. Calibration is fairly straightforward, and it is nice to be able to calibrate both the gauge and the tank levels separately. I too was confused by Holley's note that it won't work with ohm only input gauges. I have no idea what they meant by that.