The ends of the yoga bangles symbolize the main nadis (ida, sushumma, and pingala) and the rise of kundalini. They end in a single point and are unique and different, as we carve them individually. Here we explain their meaning.
If you haven't understood what chakras do, how to exercise them, and what they are for, as well as their relationship with prana and kundalini, after this brief and simple reading it will be very clear to you ;-)
According to Swami Sri Yukteswar, wearing an astrological bangle aids on the journey, beyond the physical protection that Paramahansa Yogananda experienced when his master recommended he wear it in chapter 16 of "Autobiography of a Yogi".
