Hanna Instruments are the market leader in environmental measuring instrumentation. They manufacture and supply a wide range of products including: Chemical Dosing Pumps, Chemical Test Kits, Colorimeters, Conductivity meters, Dissolved Oxygen meters, DPD Chlorine meters, Food Thermometers, Humidity meters, Magnetic Stirrers, pH meters with pH electrodes and Turbidity meters. While the catalogs of most pH and TDS manufacturers in our industry read like pamphlets with only a handful of products, the Hanna catalog is more the size of a telephone book. They have a huge selection of products that are used by individuals and companies all over the world. Their HI9813-6 combo meter has become an industry standard, while their Checker and Primo pH and TDS pens are the number one choice for economy and accuracy.