The three metal astrological bangle as mentioned in the Autobiography is made using certified 99.99% pure gold, silver & copper metals in the exact combination, structure & proportions specified by Yukteswarji and made & worn by Gurudeva Paramhansa Yogananda ji.

” MUKUNDA, why don’t you get an astrological armlet? “

“For general purposes I counsel the use of an armlet made of gold, silver, and copper.”

“One little-known fact is that the proper jewels, metals, or plant preparations are valueless unless the required weight is secured, and unless these remedial agents are worn next to the skin.”

“This problem received attention from our rishis; they found helpful not only a combination of metals, but also of plants and—most effective of all—faultless jewels of not less than two carats. The preventive uses of astrology have seldom been seriously studied outside of India.”

“Just as a house can be fitted with a copper rod to absorb the shock of lightning, so the bodily temple can be benefited by various protective measures. Ages ago our yogis discovered that pure metals emit an astral light which is powerfully counteractive to negative pulls of the planets. Subtle electrical and magnetic radiations are constantly circulating in the universe; when a man’s body is being aided, he does not know it; when it is being disintegrated, he is still in ignorance.”

“By a number of means—by prayer, by will power, by yoga meditation, by consultation with saints, by use of astrological bangles—the adverse effects of past wrongs can be minimized or nullified.”

“It is only when a traveler has reached his goal that he is justified in discarding his maps. During the journey, he takes advantage of any convenient short cut. The ancient rishis discovered many ways to curtail the period of man’s exile in delusion. There are certain mechanical features in the law of karma which can be skillfully adjusted by the fingers of wisdom”

“According to Astrological Laws to do away with all bad influences of planets, there is nothing better than a bangle. Each two bodies of the universe attract. When this adhesive power of the bodily cells becomes lax with the advance of age, the planetary pull becomes stronger, causing more laxity of cells, inviting disease and the mind to disturbance.

“The bangle and its combination of metal as fixed by the Rishis emanate electronic ray (unseen to human eyes) which counteracts all planetary vibrations. Just as a lightning rod is affixed to a house to absorb the falling thunder and lightning, so the bangle is a lightning rod to absorb the ferocity of bad planetary rays falling on the body, when disease attacks as bad karma.

“Besides, I heard Master (Sri Yukteswar) say many times that satan creates in the mind of the bangle wearer the impulse to take the bangle off, so uninterruptedly he could punish them through the instrument of bad karma of past lives. I remember definite instances of cases who almost could not wear the bangle as the arm rotted under it.

“One person had to change the position of the bangle three or four times. He was cured of paralysis and some kind of fits. The bangle will also modify and lessen any wrong influence on business. Sometimes to take the bangle off when one needs to, even in that moment, it is also dangerous. I write this only to emphasize the laws of electronic vibrations which God created and the Rishis discovered to counteract the evil planetary influence on the human body.”

From the book A Paramhansa Yogananda Trilogy of Divine Love, by Sri Durga Mata

Certain pure gems and minerals emit radiations that are beneficial to the body of man

“All things are made of vibrations, and have their own magnetic properties. Certain pure gems and minerals emit radiations that are beneficial to the body of man. One such “Bangle” made of gold,silver, and copper was recommended by Sri Yoganandaji for general use. He said that this bangle had more than physical value. (I remember his advising a disciple, who was prone to having accidents, to obtain and wear one of these bangles.)””

“A number of people who own these bangles have told me that, during times of physical illness (and, perhaps, of mental depression), their bangles have become so hot on one arm that they had to move them onto the other. I myself have felt a person’s bangle when he said that it felt hot. It was, in fact, much hotter than the arm itself–so hot that it almost hurt my fingers to hold it.”

From the book The Art & Science of Raja Yoga, by Swami Kriyananda