In 1920 Walter Pust of Jena University developed this contraceptive devices (preceding the Gräfenberg ring which was in use from 1928).
It initially consisted of a glass button, and later as in this example an iodine impregnated celluloid cap (signed Dr Pust), to which was attached silk windings and a second coil made from nylon or silk. It did not prevent normal periods and was designed to be changed every 3 to 4 months. They were not that successful and were associated with frequent infection and expulsion. The box comes with its two original instruction leaflets in German.