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Konzip conception disc

A calculation disc for indication of fertile and infertile days. The method is based on the findings of Hermann Knaus and Kyusaku Ogino from the 1930´s.

Knaus and Ogino were the first in human history, who managed to correctly identify fertile and infertile days. This counting device can be used with 28-days´cycles only. The calculation disc was produced and sold by a Styrian company for each new calendar year.

Inventory number: 1335
Material: grey cardboard, metal insert as central pivot
Dimensions, in cm: 3 x 8,5 x 8,5
Date: 1932
Condition: very good