Savinelli opted for 3 digits shape code in the 1970's.
Prior to this date 4 digits code occured.
"Non Pareil" and "Dry System" lines are exceptions to these considerations.
example : classic Billiard shape
former #: 1011 = current #: 111
regular (gr. 2.5 - 3), KS: king size (gr. 3.5 - 4), EX: extraordinaire (gr. 4.5 - 5).