After more than a century of perfecting the art of measurement through our durable weighing products, OHAUS precision is now available in a line of pen meters that provide accurate measurement of pH, oxidation-reduction potential (ORP), conductivity, salinity, and total dissolved solids (TDS). Starter pen meters are the economical option when you are simply looking for meters that will provide accurate measurement without restriction. Applications pH, oxidation-reduction potential (ORP), conductivity, dissolved oxygen (DO), salinity, total dissolved solids (TDS), temperature measurement Display Liquid crystal display (LCD) display with secondary information line (on select models) Operation 4 1.5V batteries (included) Communication N/A Construction ABS Housing Design Features Easily replaceable electrodes, automatic shut off feature