NOT SUITABLE FOR BLACK PURIFICATION ELEMENTS.
A Pair of Berkey PF-4Fluoride and Arsenic Reduction Elements for the Berkey Earth Filter
*The PF-4 Fluoride and Arsenic Reduction Filters are made and assembled in the USA
PF-4 Fluoride and Arsenic Reduction Filters adsorb the following unwanted elements found in drinking water:Fluoride
Arsenic
Lead
Heavy Metal Ions
MTBE (Methyl-tertiary-butyl-ether)
Trihalomethanes (THM)
DBCP (Dibromo-chloro-propane)
Herbicides and Pesticides
Made from safe, non-leaching Polypropolene #5 that is BPA-free
Sold in a set of 2
PF-4 Fluoride and Arsenic Reduction Filters are designed to be used in conjunction with the Berkey Earth Elements or the Super Sterasyl Ceramic Filter Elements 
Attach to the bottom of the Berkey Earth  Elements or the Super Sterasyl Ceramic Filter Elements and sit in the lower chamber of the Berkey unit
Number of PF-4s in the bottom chamber must match the number of Berkey Earth Elements or Super Sterasyl Ceramic Filter Elements in the top chamber; for example, 2 Berkey Earth Elements would require 2 PF-4 Filters
PF-4 Filters need replacement after six months