I have several gauges in my car. Oil Pressure, Oil Temp, Water Temp. I got some off ebay, and they came with all the sensors required, the oil ones plugged into a sandwich plate that came on my car when I bought it (I was replacing some tired/broken gauges) and the water temp sensor had just been put into a hard pipe. What does get sold is a metal sensor screw in thing tht can be put into your radiator hosing somewhere, so I'm guessing that the gauges just don't come with all that stuff, and you'll need to buy some of it extra.