ALL OF THESE FLAT CAP SURFACE SNAPS ARE MADE FROM ZINC ALLOY. THE OTHER TREE PARTS ARE MADE FROM BRASS. THESE SNAPS HAVE BEEN TESTED WITH 12MM FASHION DIE SET LISTED (ON MY WEBSITE AS PREORDER) USING KAM TABLE PRESS IN MY GROUP. I CAN NOT GARANTEE OTHER DIES AND PRESSES WILL WORK. I HIGHLY RECOMMEND YOU TO ORDER MY DIE FOR THIS SNAP.