Long story, but Caerbont finally replaced my coolant gauges after a year. I switched to electronic gauges, so I no longer need these.
I have two and they are brand new. They use a slightly different adapter than the older versions. Range is 30-120 Celsius, usually run around $150, offering at $75, code TG1301-30C078 mechanical gauge
This is the diagram for the gauge adapter that is included.