Ohaus Starter TDS Pen MetersCompact Design for Fast, Convenient Electrochemistry Measurement At Your Fingertips OHAUS precision is available in a line of pen meters that provide accurate measurement of 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. With low (100mg L) and high (1,000mg L) range models and temperature