This professional silver testing kit provides everything you need to accurately determine the karat content of your silver jewelry and items. The set includes 3 bottles of silver acid solutions - each in a generous 3/4 ounce (22ml) bottle that's good for hundreds of tests. The kit comes complete with a durable black testing stone and comprehensive step-by-step instructions. The testing process is straightforward: simply create a mark on the stone with your gold item and apply the testing solution to determine the karat purity. The solutions are carefully packaged in secure, vacuum-sealed bottles for safe handling and storage. The included black stone features two usable sides for maximum utility. Whether you're a jeweler, collector, or simply want to verify your gold items, this testing kit offers a reliable way to check silver purity from 500 to up to 999. The clear instructions guide you through the testing process and help interpret results based on how the metal reacts to the testing solutions.