The mineral ion filter brings you clean, crystal clear hot without high levels of heavy chemicals. The active ingredient is zinc. (The inert ingredients are vitamin C, calcium sulfate, zeolite, attapulgite clay, zinc oxide, and magnesium oxide.) You can see, smell and feel the difference as spa mineral filters improve water quality. Easy to install and low maintenance, compatible with most spa maintenance products. Excellent cleanability allows your hot tub filtration system to release maximum filtration power when cleaned, reducing spa maintenance costs. Maximize your spa's performance, reduce energy costs, and reduce operating stress on your filters and hot tub, extending their lifespan with Mineral Technology. Superior high-efficiency filtration material designed for durability and cleanability, the reinforced mineral filter rod can be used with both cold and mild hot water spas. Colour:grey Material:plastic+metal Package Contents: 3 x filter rod 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.