The BWT besthead filter head is a smart technological solution that can be fixed to any BWT water+more filter, so you only have to purchase it once! The bypass is easy to install, can be used repeatedly, and is safe. A non-return valve on the inlet side prevents any ingress of water into the drinking water system and a similar valve on the outlet side seals the filter off from the end device (e.g. coffee machine). Both non-return valves close if there is a sudden drop in pressure, which prevents leakage and water discharge during replacement of the filter. The dual system is rounded off by the BWT bestflush bleed valve, which is what makes this technology unique.