These days we see two types of cappings that are applied to rudraksha beads (only single bead is worn in a mala).
1 - Rudraksha bead pin capping.
Here one pin is inserted through the center hole and a circular shape at one end is made for thread pass through.
2 - Rudraksha bead circular top bottom capping.
Here one pin is inserted through the center hole along with two immitation circular caps at both ends. Then one circular shape is made at one end for thread pass through.