Gaffrig by Livorsi is the gauge that you would want. This is the company that supplies gauges to Fountain, Cigarette, Donzi, Baja, and just about every other performance boat manufacturer. They are located in Grayslake, IL and owned by Mike Livorsi. Phone number is 847-548-5900. I live near this company, have been there many times (yesterday), and have nothing but great things to say about everyone involved. Mike Livorsi will talk to you himself if you can catch him between phone calls.
There are two companies utilizing the Gaffrig name. Gaffrig Performance that Timucin linked to is not likely the company you are thinking of when you hear the name Gaffrig. I know nothing about the quality of their product. They are a competitor to Gaffrig Livorsi.
I can attest for the Gaffrig Precision Instruments (Livorsi) company as my Donzi came equipped with their gauges, I have installed their GPS speedo and I had them install an "Extreme Supercharger". All of their products have worked perfect in my application. The supercharger took my Donzi from 64 mph/gps to 80 mph/gps with no reliability or driveability issues.
Their is a lawsuit involving the Gaffrig name so I aint gonna get in the middle of who/what/where.
Once again, I have no financial interest in this company. I am just an EXTREMEly satisfied customer - past, present and future.