Feature 1Completely waterproof. The battery compartment is sealed against accidental splashing or brief submersion under one meter of water or plant food. 2Measures EC (electrical conductivity), CF (conductivity factor) and PPM (parts per million) scales. 3High conductivity measurement for a broad range of crops. 4Factory calibrated. 5Auto turn on and off function activates truncheon when put in to, or taken out of solution. If you use hydroponics to grow your own fruit and vegetables then you'll know how important it is to get the mix of the nutrients that you feed them just right. This truncheon nutrient meter is so quick and easy to use and will give you accurate results time after time. All readings are displayed on the meter-no need to consult books or manuals. Just dip into your solution and read. The proper combination of nutrients = top quality fruit and veg Reads: EC (electrical conductivity) CF (conductivity factor) PPM (parts per million) Great Benefits: Simple to read results-flashing LED light scale gives you all the info you need Accurate readings every time-truncheon is factory calibrated (further calibrations can be carried out easily with EC 1.4 buffer solution on regular basis to keep accuracy). Use in varied environments-completelytemperature compensated Secure from water damage-100%waterproof Longer battery life-auto on/off function activates truncheon when put in to, or taken out of, solution User-friendly 2 step process to taking your reading How Do I Use My Truncheon? 1. Place the head of the probe into the solution for 1-2 minutes so that the temperature of the probe and the liquid are the same. Remove probe. 2. Place the probe back into the solution. The LED lights will indicate the nutrient levels 3. Rinse probe and replace cover. That's it Features: Completely waterproof. The battery compartment is sealed against accidental splashing or brief submersion under one meter of water or plant food. Measures EC (electrical conductivity), CF (conductivity factor) and PPM (parts per million) scales. High conductivity measurement for a broad range of crops. Factory calibrated. Auto turn on and off function activates truncheon when put in to, or taken out of solution. No external knobs or switches. Step by step instructions included. new and boxed. Specifications: Range 0.4-5.2EC; 4-52CF; 280-3640ppm(EC * 700) 200-3000ppm;(EC * 500 Resolution EC:0.1; 1CF; 70ppm; 700 50ppm; 500 Accuracy 4% Operating Temperature 0-50 C; (32-122 ) AutomaticTemperature Compensation 0-50 Battery 3*AA battery(Not included) Size 415*25*25mm/16.3*1*1in Weight 103g/3.6oz Package List: 1*NutritionWand 1*Manual 1*Plastic Box Note: Because there was a manual measuring ,the size may has 1-2cm/inch difference.