Over the years I've owned lots of thermometers but they never last. Last year I found one that can stand up to the kind of abuse I dish out - the Fishpond Swift Current. It's a laboratory-grade unit protected by aluminum case. It provides accurate water temperature readings (20 to 120 degrees Fahrenheit) under a variety of salt and freshwater fishing conditions. It can easily be attach to a D-ring so it goes with you everywhere. At $18.00 it's not the least expensive unit you can buy but it's outlasted every product I've tried.