The DIW-10 provides approximately 150 gallons of mineral-free, de-ionized water based on your water input quality. It consists of two 10 inch de-ionization housings that feature replaceable and/or refillable cartridges that simply slide into the watertight tubes. This unit is designed to be mounted on the wall and comes with pre-drilled mounting holes. The advantage of using this system is that you can rinse your vehicle and walk away without having to worry about water spotting - no drying towels required!