[High-quality sponge material]Traditional sponge balls have large pores on the and are prone to yellowing. The upgraded spa hot tub descaling balls are not only made of high-quality sponge material, but also have a whisker-like . The upgraded sponge material can effectively remove dirt, body oil, foam and other residues, absorb fine impurities to the maximum extent, and are not easy to turn yellow and fall off, ensuring that your pool/hot tub stays clean and tidy! [Absorbs grease and all dirt]Our spa hot tub descaling balls can absorb more than 41 times its own weight of inanimate dirt. These reusable descaling balls effectively absorb and eliminate grease, debris, pollen and other pollutants in swimming pools, hot tubs and spas through capillary action and tension. [Elastic and reusable]The upgraded sponge material absorbs pollutants without dissolving. The oil-absorbing sponge balls are washable and flexible. After use, you can squeeze the water out of the sponge balls and wash them after use. They will quickly return to their shape for cleaning, saving time and affordable. It is a must-have for every swimming pool or hot tub owner. [Easy to Use]Simply place the scum balls in the hot tub sponge in your pool or hot tub, and their unique floating design allows them to move effortlessly, cleaning all surfaces without any manual labor. Once full, simply squeeze out the oil, rinse the sponge and use it again. [Gentle Cleaning]Unlike traditional pool chemicals, these floating filter balls naturally eliminate dirt through physical absorption without introducing any harsh chemicals into the water. Provides an environmentally friendly way to keep pool, hot tub and spa water crystal clear or harm users; Colour:White Material:sponge Size:about 3inch Package Contents: 8 x Hot Tub eaner Balls Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.