The Triplett Model CD100 waterproof (IP57) Conductivity/TDS/Salinity Pen measures TDS, Conductivity, Salinity and Temperature. It simultaneously displays Conductivity, TDS, or Salinity and Temperature and has an analog bargraph for viewing trends. It features ATC (Automatic Temperature Control) that compensates for temperature changes, adjustable TDS compensation ratio, 1-, 2-, or 3-point Conductivity calibration, and a RENEW warning when probe needs cleaning or replacement. Additional features include the ability to store/recall 25 readings, a Hold function that "freezes" the reading on the display, and Auto power off (after 10 minutes) with disable conserves battery life. Includes meter and electrode with protective cap, (4) CR2032 batteries, sample cup with cap, and neckstrap.