MobyDuo Bead. Moby Duo beads are a 2-hole Czech glass bead, with a design that looks like the back of a breaching whale inside of your jewelry designs. MobyDuo can also be used as a spacer. You will love using the MobyDuo bead in your beading projects! Each tube of Moby Duo contains approximately 90-95 beads. Each has a 3x8mm size.