Bought brand new and used only twice. The Hanna Marine Master Test Kit is a comprehensive testing solution specifically designed for marine aquariums. Made by Hanna, a reputable brand in water testing, this kit enables users to accurately test various parameters such as alkalinity, ammonia, pH level, nitrate, calcium, phosphate, magnesium, and nitrite. With a focus on marine water types, this test kit is perfect for pet owners and hobbyists looking to maintain optimal water conditions for their aquatic pets. Made in the United States, this product ensures quality and reliability in testing aquarium water.