I found these drums in the basement of an old Philadelphia rehearsal building.  The drums have etched on the sides, "Crafted by Fred Hinger, 1967".  When Hinger was playing in the Philadelphia Orchestra, he at times took old Leedy copper bowls and converted them to the Anheier cable hand tuning system.  These particular drums have 3" extended collars, and sound so warm and deep.  Probably the best sounding timpani I own.  The chain conversion was not cheap, but it was well worth it, as I now have very reliable and beautiful sounding instruments.   And they are a real piece of Philadelphia history!