Calibrating a digital thermometer

Anyone have one of these digital thermometers...Digital Thermometer w/Probe :: Midwest Supplies Homebrewing and Winemaking Supplies.

It's way off and I can't find any info on the net where it says how to calibrate it.

The best thing to do IMHO is to buy a calibration thermometer aka lab thermometer they are fairly inexpensive $5-6 and then record the results in a note book or on the back of the digital thermometer so that you'll know if for example your digital thermometer says 150*F but your calibration thermometer says it's really 145*F you'll have a reference to know exactly where you are temperture wise

You should probably record every 5*F in the range you be using say starting at 140-180*F and then just extrapolate for the in between readings