Brizo Pristive™ Reverse Osmosis Pre-Filter ReplacementThe Pristive Pre Filter is an external filter (inline or inlet tubing) that helps minimize clogging and enhances the systems efficiency. The pre filter lasts for up to 3,950 gallons, or around six years, whichever comes first Features: Compatible only with the Pristive Tankless Reverse Osmosis System, this external filter (inline on inlet tubing) helps minimize clogging and enhances the systems efficiency. Replace filter every 3,950 gallons, or around