Control Wizard E.C Dipstick™
Now with the 4 most popular scales: EC, CF, 500:1 ppm, and 700:1 ppm! The E.C. Dipstick dissolved salts pen operates on 3 common inexpensive AA alkaline batteries. Measures in PPM, EC and CF scales. There is no calibration required. It calibrates itself each time you replace the batteries. The EC Dipstick is waterproof to one meter.