After getting frustrated with low quality thermometers, I decided I might as well get me a decent one and I bought a
"Therma K Plus " thermocouple type unit.
http://www.thermoworks.com/products/handheld/therma_k-plus.htmlNot cheap, but I think it is a case of getting what you pay for. It is a very rugged unit meant for commercial use - I also bought a silicon boot to protect it further
It is supposed to be accurate to about a half a degree and can use a wide variety of plug in probes - hand held ones and wires.
Each unit is individually calibrated and is provided with a calibration certificate. I think they are made in the UK.
I have had it about since last Spring and am extremely happy with it - I have a couple of hand held probes and two 10' long wire sensors that I drop into my mash tun and hot liquor tank. They just plug into the unit. I would certainly buy it again
Brian
PS - it has also turned out to be the best BBQ thermometer I have ever owned (Used that to justify the purchase to SWMBO).