EC Dipstick (formerly Nutrawand) by Control Wizard Products. New Name! New Label! Same Easy to Use Meter! Now with the 4 most popular scales: EC, CF, 500:1ppm, and 700:1ppm! No matter what meters you have used in the past, the EC Dipstick can read just like it. EC Dipstick (formerly Nutrawand) by Control Wizard Products dissolved salts pen, measures conductivity in both PPM, EC and CF. No calibration required, auto on/off. Very Nice!Over the years Control Wizard Products' EC Dipstick (formerly Nutrawand) has proven to be a rugged performer and great conductivity meter that everyone that owns one seems to love. Why, well they just seem to work harder the more demanding the situation. It's great for greenhouse use where high moisture situations exist or in classrooms where students are learning how to care for tools. The meter is waterproof to 1 meter for short periods of time. Its new electronics allow for hassle free operation. It does not require calibration like other meters. Calibration is all handled internally within its electronic brain. Each time you replace batteries it recalibrates itself. Wow, how cool is that? The savings in calibration solution over 5 years alone makes this meter a real buy. It measures conductivity in 4 scales: EC, CF and 2 PPM scales. EC stands for electrical conductivity, PPM stands for parts per million and CF stands for conductivity factor. Conductivity factor is simply ten times the EC reading for easy reference (1.5 EC reads 15 CF). Another feature that's a real advantage is with just a glance, the EC Dipstick allows you to easily read all scales at once. Well-placed blinking LED lights show you the conductivity of your nutrient from a brightly printed scale. This is one instance that new technology has actually made the product easier and more fun to use instead of hideously more complicated and time consuming. Want icing on your cake? This meter uses three inexpensive AA flashlight batteries. This meters worthiness should be a no-brainer for all growers young and old. This meter comes with a limited two-year warranty with your original sales receipt.