Fully waterproof, not just water-resistant Selectable measurement units so you can customise with your preferences Flat electrode for easier cleaning and maintenance Hold reading function to capture every measurement with ease Automatic temperature compensation for accurate readings anywhere Auto-off function to extend battery life 1 x AAA alkaline battery included, getting you started immediately Providing quick and accurate readings at the click of a button, you can rest assured that the user-friendly Bluelab Conductivity Pen will give you reliable results, every single time. In addition, this product offers a range of in-built measurement units, so you’ll be able to customise it according to your preference. For conductivity readings, you can choose between EC, CF, PPM 500 (TDS) or PPM 700; for temperature, you can select ˚C or ˚F.