The measurement is 4mm. Flat on one side and a single groove down the center on the other. Yummy and unusual to come by. Made in Czechoslovikia. They are from the early 1900's. What a find! Glass nailhead beads were used in the days of the flapper to embellish garments before sequins were developed. Also sold in lots of $6/48, item #9593.
If you are not delighted with your beads and beading supplies, we will gladly give you a store credit, exchange , or a refund within 30 days of purchase. Please see our shipping & returns page for the full details.