Humbly suggest the DTC375 by CDNW:
Thermometers – CDN – The Time and Temperature Company
I use one everyday at work, and my candy batches never fail. More, it is now the gold standard, and ALL of the other analog thermometers are calibrated against this one.
OTOH, it is neither waterproof nor NSF rated. So, to clean, you can only use a damp cloth to clean the plastic, red, upper bits of it.