**Safe Material:** These well-designed spa mineral sticks are crafted from high-quality ABS plastic, making them sturdy and odorless. The minerals contained within are harmless to the human body, so you can use them with complete confidence. The mineral inside the spa mineral stick effectively absorbs certain impurities in the water, creating a better and safer water environment for you to enjoy your spa. **Features:** **Easy to Install:** Hot spring mineral sticks are not affected by heat and can be installed over your existing flow. Simply place the spa stick into the existing filter, and let the new stick do its work. **Natural Mineral Substance:** Ensures your spa has no odor, enhances spa performance, and provides you with crystal-clear, clean, and fresh water without harmful chemicals. **Suitable for Most Spas and Hot Tubs:** Compatible with Jacuzzi tubs, inflatable tubs, niche tubs, walk-in tubs, bubble tubs, spa boats, and the easiest-to-use standard tubs that take only seconds to install. **Perfect Choice:** Our hot tub stick can treat up to 500 gallons/2000L. Our maintenance-free, low-cost spa cartridge lasts up to 4-6 months, saving you time and money. **Natural Hot Spring Experience:** Natural hot spring mineral paste can automatically add trace elements to the hot spring, reduce impurities in the hot spring, make the water clearer and cleaner, and make you feel as comfortable as if you were in a pure natural hot spring. **Package Including:** Set of 2 yellow spa filter sticks ONLY; other accessories are not included!