The measurement of these vintage nailhead beads is 4.5mm round. These are round on one side and flat on the other. The shape reminds me of the old dots candy on the strips of paper that I used to have as a child. Great size and shape. Made in Czechoslovakia. They are from the early 1900's. Glass nailhead beads were used in the days of the flapper to embellish garments before sequins were developed. We can date these back to the early 1900s. You receive 24 beads per lot.