Tri-Electronic’s Gt-4000 Gold Tester detects karat value of gold from 6 to 24 Karats in all four colors: Red, Yellow, White, and Green. Accurately tests from 6 to 18 and 24 karats values then a range of 20-22 karats. A numeric reading corresponds to the karat table provided shows on the LCD Display of the GT-4000 Tester. Ecologically safe, there are no dangerous acids or messy harmful chemicals. The GT-4000 includes the Tester unit, Sensor with protective cap, TB-24 Gel Tube, Testing Plate with alligator clip, File, Plastic Sensor Cleaner, Cable Connector, Karat table, eraser and FREE Jewelers Supermarket Cloth. Powered by two 9 Volt Batteries included and installed in the back of the GT4000 Two Year Manufacturer’s repair or replacement warranty.