This transparent aqua mouth blown Venetian Bead is approximately 20mm with hole ranging between 1.5mm and 2.5mm. As they are blown at about 840-900 Degrees Centigrade, it is impossible to control the exact hole size. We recommend using bead caps as it helps stabilize the bead. These are stunning when made into your Venetian Glass Jewelry, as they are larger but still light weight. Per Piece.