Neptune Systems DOS Replacement Head Cap Genuine Replacement Pump Head for the Neptune DOS Dosing System The Neptune Systems DOS Replacement Head Cap is a genuine replacement pump head assembly designed for the Neptune DOS Dosing & Fluid Metering System. This complete assembly includes a new head housing, peristaltic tubing, fittings, and roller wheel, allowing you to restore your DOS pump to peak performance with a quick and simple replacement. As the peristaltic tubing naturally wears over time, replacing the head cap helps maintain accurate dosing, smooth operation, and long-term reliability. Neptune Systems recommends replacing the DOS Head Cap approximately every 700 hours of pump run time, depending on usage. Key Features Genuine Neptune Systems replacement part Complete replacement pump head assembly Includes head housing, peristaltic tubing, fittings, and roller wheel Restores dosing accuracy and pump performance Quick, tool-free installation Helps reduce wear on the DOS motor Compatible with freshwater and saltwater aquariums