Schluter-KERDI-BOARD-ZT are galvanized steel washers used to fasten KERDI-BOARD to metal or wood stud framing. They feature tabs that penetrate the surface of the KERDI-BOARD and temporarily hold the washers in place to enable quick installation of the corresponding screws. KERDI-BOARD-ZS are coarse thread screws used to fasten KERDI-BOARD to wood stud framing with the corresponding washers. Warning: This product can expose you to chemicals which is [are] known to the State of California to cause cancer and birth defects or other reproductive harm.