The head changes temps the fastest and is hotter then the water temps.
It comes with everything you need but the mount.
The head sensor has a O-ring that when you remove your spark plug, you slip the ring on the bottom of the plug and screw the plug back in... Simple...
Take the gauge and double face tape it to your mount... Simple...
Go ride
The Left gauge is the head temp, and the Right gauge is the water temp on the outlet.
I need a third on that shows me the water as it is exiting the head.