RR Oil Temperature Gauge :

The practical display of current oil temperature. RR oil temperature displays are absolutely protected from vibration by their Teflon bearings. You will only come to appreciate this instrument once you’ve tried it out: it collects actual values, leading to a healthier warm-up phase or even to the prevention of engine damage - all instantly available without the stress of extra installation.

At the same time it’s of crucial importance to know that coolant and oil temperature is not the same thing. Made in Germany.
The “Tourenfahrer” magazine test results: “very good” accuracy, “worth every penny”. And to avoid the problem of needle vibration, the instrument is filled with glycerine (an integrated air pocket looks after pressure compensation).