The bottom side of a German-made Sound Formula, showing the 80s-era PAisTe stamp. As this is a Signature-bronze cymbal, patent info is stamped on the underside of the bell, as well as the words "Made in Germany".
Later Sound Formula "Frankenstein" logo. Used on Swiss-made Sound Formulas 1994 to 1999. As these are professional-quality cymbals, the words "Professional Standard" were added to the series stamp.
