Accurate Thermometers

Forgive me, I already posted this--but it appears I listed it as a "comment" and not a "discussion."

Does anyone have a thermometer that they especially like (that seems to maintain accuracy). I have various thermometers, classic bulb style, dial/analog, and digital, and none is reliably accurate. I tested them all by immersing them in boiling water, which should be around 212 F. The various devices measured between 180 F and 230 F. Only two out of 8 thermometers were within 5 degrees of 212 F. When I'm making caramels that need to be cooked to within a couple of degrees of the desired temperature, this inaccuracy and variability is frustrating. Does anyone recommend an accurate, reliable brand and model? Thanks!