This Pro Bead Roller will roll two bead sizes, both ovals. One is 19 x 7 mm, the other is 18 x 9 mm. The beads rolled with this set can be pierced while the bead is inside the bead roller, avoiding the possibility of fingerprints or distortion from handling the bead to pierce it. Bead pins sold separately. See our Bead Rack designed to hold the bead piercing pins for curing or finish coating beads, a must have for serious bead makers!