Bluelab's pH Pen is the most streamlined, convenient, and simplest to use measuring devices that we've ever encountered. Rivaled only by their Truncheon meter, Bluelab's Pens are packed with awesome features. They come loaded with automatic temperature compensation (ATC), 0.1 pH increment readings for accuracy, and are completely waterproof. We've left these things floating in reservoirs with no ill effect!
Everything about this pH pen is intended to make all aspects of use as easy as possible. They're lightweight and slim for single handed use, automatically compensate for temperature, automatically shutoff to save batteries, calibrate with a simple two step process, and come with a one year warranty for peace of mind. They also measure temperature alongside pH so that you get both readings simultaneously!
1 year warranty