4mm x 1mm metallic blue iris glass bead. These tiny tubes have tiny holes as well, so use size 15 beading needles and O or OO beading thread. One hank contains twelve 20 inch strands.Czech maco tubes are tiny tube beads briefly produced during the 1990's then discontinued. We like to describe them as liquid silver. They are the creme de la creme of bugle beads used by some top designers for fine embroidery work. These fine maco bugle beads are all temporarily strung in hanks for your seed beading and weaving convenience. Simply tip your needle through the string and take off what you need. This is one of the nice features of beads sold in hanks.