Crystal gold rainbow Super Duo Beads are a Czech made, glass Two Hole Seed bead. Similar in shape to the Twin bead but with a few very important differences. Super Duos are a pressed glass bead with guaranteed size and dimensional stability. They measure 2.5x5mm with two 0.8mm holes. They are not simply coated crystal but actual coloured glass. Comes in 24g vial. Approximately 315 beads.