Astrological bangles are recommended by Paramhansa Yogananda and his guru, Sri Yukteswar. They can strengthen your aura and deflect or mitigate negative karma. They protect one from negative astrological influences.
They are created using a specific formula prescribed by our line of gurus and passed down through Swami Kriyananda. If you read chapter sixteen of Autobiography of a Yogi, you will find more information about astrological bangles as described by Paramhansa Yogananda.
They are made with pure gold, pure silver, and pure copper. These pure elemental metals are formed into the bangle with heavy round wire which are twisted together in a spiral helix pattern. The cost of a bangle depends on the price of gold at a given time. They can be worn directly above the elbow, above the bicep muscle, or around the wrist. Paramhansa Yogananda has recommended that you wear your bangle on the upper arm above the elbow. When you are wearing your bangle it is fine if the ends touch where they overlap.
It is important to have your existing bangle annealed periodically. The frequency of the annealing/cleaning process is determined by the level of stress your bangle encounters. If you take it on and off or if you wear it on your wrist, you will need to do this more often. Also encountering and passing through challenging or powerful periods of karma can lead to more frequent annealing. Eventually, the metals absorb so much stress that they harden and the metals can crack and break. Annealing will relieve residual stress and render the metal softer and more ductile. This process can reset the energetic balance of your armband.