If you live in an area where the water is hard, full of minerals, and are tired of seeing your car-washing efforts end up in water spots, then we have a great solution for you. This In-Line Water Softener & Deionizer removes minerals from tap water to end those dreaded spots. Now it's possible to rinse the car and dry it off without the worry of my glass and paint spotting before you can get to it. Simply attach to your hose spigot. The green crystals change to purple, indicating when it's time to replace the filter. A revolutionary way to give your car that final rinse. Measures 13" long, 4 1/4" in diameter. Fittings included.