BWT Bestmax Filter Cartridges provides you with a universal filter system that optimizes your raw water to your specific requirements. A blended partial flow (0–3) is adjusted at the filter head depending on the water hardness and requirements. Check valves in the filter head prevent any water from back flow into the drinking water mains or filter cartridge and protect against uncontrolled water discharge. BWT bestmax food-safe filter systems are pressure-resistant and safe. They can be used worldwide in any drinking water system.