The 5x Hot Springs Silver Ion Cartridge Spa Mineral Sticks are designed for hot tubs and spas, specifically for a capacity of 600 gallons. Each stick is made of plastic and is 16.5 cm long, 3.5 cm high, and 3.5 cm wide, with a weight of 0.15 kg. These mineral sticks are blue in color and round in shape, providing easy installation for all water types. They are designed to help maintain water quality by releasing silver ions into the water, and are suitable for use in various hot tubs and spas.