UT520 series can perform precise 3-wire and simple 2-wire earth resistance measurement for power and electrical systems, lightning protection equipment, and ground system of all electrical equipment. This series is introductory earth resistance tester with high economic value. Its lightweight design is convenient for fieldwork. Features: 1. Over range indication, test lead connection alarm 2. TEST button for fast capture of measurement values 3. 20-group data storage/recall 4. Backlight 5. Data hold 6. Auto power off/battery check 7. Earth voltage measurement Specifications Range Accuracy Model UT521 Earth Resistance (??) ??~20?? ??(2%+10) ??~200?? ??(2%+3) 0~2000?? ??(2%+3) AC Earth Resistance (V) 0~200V ??(1%+4) Frequency: 50Hz/60Hz yes Features Display Count 2000 Manual Range yes Auto Power Off About 10 minutes yes Low Battery Indication yes Data Hold yes Data Storage 20 LCD Backlight yes Full Icon Display yes Double Insulation Protection yes Contact Badness Indication Port C or Port E don't contact display"---??" yes Overload Indication Display "OL" yes Simple 2-Wire Testing yes Precision 3-Wire Testing yes General Characteristics Power 1.5V AA Batteries * 6(not included) LCD Size 70.6*34mm/2.8*1.3in Product Color Red and grey Product Net Weight 560g Product Size 160*100*70.5mm/6.3*3.9*2.8in Standard Carton Gross Weight Approx.2112g/74.5oz Package list: 1 * UT521 Earth Tester(battery not included) 2 * Auxiliary Ground Nails 1 * Protect Shell 1 * Cloth Pouch 2 * Crocodile Clip Test Lead (green + red) 3 * Standard Test Lead with Clip(green + yellow + red) 1 * Instruction .