1 cardboard sheet : illustration ; 23 cm + 1 booklet (8 x 14 cm)
Summary
Depicts a perpetual monthly calendar in shape of a circle divided to 3 segments: for 28, 30 and 31 days, and a dial with Scale "A" (showing sterile and fertile days) and Scale "B" for regular and irregular cycles. It is designed to predict a woman's fertile and non-fertile period based on her menstrual cycle
Notes
The booklet of instructions consists of 12 stapled pages and attached to the bottom of the cardboard sheet
Based on the work of a Japanese doctor Kyusaku Ogino
