Features: 1.Natural Spa Experience: The nature spa mineral stick can automatically add trace minerals to the hot springs, reducing impurities in the hot springs to create clearer and cleaner water, making you feel as comfortable as you are in a pure natural hot spring! 2.Extend Life: This silver nitrate stick can extend the life of spa, keep the crystal clean, keep your spa sparkling clean and fragrant, and make the guest's spa experience unparalleled! 3.Exist for High-cost Performance: This hot springs silver ion stick is based on a product that was born through market research and customer needs. It has a maintenance for time of up to 4 months, and the maintenance cost is extremely low. It can be used in conjunction with your existing filter. Just put your hot tub stick in the filter. You can enjoy a for carefree spa experience for 4 months! 4.Easy to Install: This silver ion cartridge hot springs stick is equipped with a complete manual. The installation can be completed quickly according to the steps of the manual and is not affected by heat. It can be installed at the existing flow rate. Just put the hydrotherapy rod into the existing filter, and then Let the hot tub stick work. 5.Applicability: The minimum required filter length for spa hot tub filter mineral rod parts is about 6.5 inches, and the minimum filter hole diameter is 1-1/4 inches; suitable for spas and hot tubs up to 500 gallons / 2000L. Specifications: Material: Plastic Total Length: Approx. 41cm/16in Package Includes: 1x SPA in-Filter Mineral Stick note: Please allow 1-2cm errors due to manual measurement, make sure that you do not mind before you order. Due to the difference between different monitors, the picture may not reflect the actual color of the item.