IrisDuo - Zinc Iris. This 2 holed bead features a flush bottom and domed top, both of which can be used as a focal point in your designs. The IrisDuo’s marquise, petal like shape and smooth edges will make this one of your favorites to incorporate into your beading projects. These high-quality, durable beads are made by PotomacBeads out of pressed Czech glass. They measure 7x4mm with a hole size of .8mm and come in a pack of 300.