The Paterson Color Thermometer is designed for color processing due to its accuracy, but can be used with all photographic processes.
This glass spirit thermometer is 12" (30cm) long, and has dual temperature scales from 15°C to 65°C and from 60°F to 130°F.
Accurate to + 0.14°C (+ 0.25°F); Recommended for all color processes.
Just trying it today and it reads around 15ºC off, which is a ton. I had it sitting in the cupboard for 2 months before using it, but today I'm now trying it and giving it many long chances to read more accurately but so far it has been to no avail. At this point, If someone chimes in about its time in the cupboard being the issue, I'll change or delete my review.
This thermometer arrived with the fluid column split into several sections, all quite a few degrees apart from each other. I checked many analog photo blogs and see that this is a common problem with alcohol-column thermometers. To date, none of the recommended repair solutions (tapping, centrifuge) have worked to get the column fully rejoined. If you can use a thermometer with a metal probe and a dial readout, I'd suggest that as a better choice than this Paterson.