Vintage Czech green flat square nailheads. 4mm. Rare! Strand of 25 b17-073

4mm square x 3mm thick. These are a flat on the back with a faceted front. They are single strand. Glass nailhead beads were used in the days of the flapper to embellish garments before sequins were developed. Very rare!. These are marked Czecho-Slovakia, dating them between 1918 and 1934. Strand of 25