Yes, the BOROUX Proactive\u2122 Fluoride filters are designed to be fully compatible with Berkey water filters. They are attached directly to the Black Berkey filters and therefore sit in the lower chamber, just like Berkey\u2019s fluoride filters. This allows you to continue using your existing Berkey system whilst benefiting from BOROUX\u2019s advanced fluoride-reducing technology. They will, of course, also fit into the housings of other brands\u2019 gravity-fed water filters, provided that Black Berkey filters or BOROUX Foundation\u2122 Black filters are used.<\/p>\n\n\n\n