The Zodiac Nature2 Spa Mineral Stick is a cartridge filter designed specifically for hot tubs, lasting up to 4 months. This 3 pack of mineral sticks from Zodiac is a convenient and effective solution for maintaining clean and clear spa water. The Nature2 model ensures efficient filtration and mineral purification, providing a relaxing and enjoyable experience for hot tub users. Perfect for those looking to extend the life of their spa filters and keep their hot tub water in top condition. Destroys Algae Bacteria: Effectively kills bacteria and contaminants using silver ions. Family Friendly: Nature2 reduces the potential for red eyes, skin irritations and odors by reducing the need for harsh chemicals. Lasts 4 Months: To continue enjoying benefits of your new spa, replace your Nature2 SPA mineral sanitizer every 4 months. Controlled Release Technology: Nature2 automatically dispenses the right amount of mineral ions into your pool water for continuous sanitizing and healthier pH levels. The Ultimate Spa Experience: Save time and avoid the hassles of traditional chemicals. Nature2 is simple, effective, and more convenient than conventional spa sanitizers.