Yusei, Spira and Ota Rings

2 Yusei rings with and without a metal ring in the middle, 2 Ota rings made of nylon in sizes medium and small, 1 Spira ring, also from the inventor of the Ota ring, Dr. Tenrei Ota. Mounted on black cardboard.

Inventory Number
1867
Material
polyethylen, metal, cardboard
Size in cm
16,7 x 10 x 0,3
Condition
very good
Donor
Univ. Prof. Dr. Robert Snowden