[Safe Material] These well-designed spa mineral rods are made of quality ABS plastic and are sturdy and odorless. The minerals it contains will not cause any harm to the human body, so please feel free to use them. The mineral inside the spa mineral rod can effectively absorb some impurities in the water, creating a better and safer water environment for you to enjoy the spa. Features: Easy to Install * Hot spring mineral rods are not affected by heat and can be installed on your existing flow. Simply place the spa rod into the existing filter and let the new rod work. Natural Mineral Substance * Ensure the spa is odor-free, improve spa performance, and bring you crystal clear, clean, and fresh water without harmful chemicals. Suitable for most spas and hot tubs * Suitable for jacuzzi tubs, inflatable tubs, niche tubs, walk-in tubs, whirlpool tubs, spa boats, and standard tubs. The easiest to use, they only take seconds to install. < p>Ideal Choice * Our hot tub rod spa can hold up to