The term Navagraha denotes the nine celestial bodies which are central to astrological calculations (and beliefs & not the nine planets as it is frequently erroneously translated). The Sun, Moon, Mars, Mercury, Jupiter, Venus, Saturn and the two shadow planets Rahu and Ketu constitute the Navagrahas. The nine "grahas" or planets in our horoscope control our karma, our desires and their outcomes. Each of these nine planets exerts an influence in our lives, which is called "dasa" and it can be known from one's horoscope.
Navagraha Pendant should be worn to reduce the negative effects and to improve the positive energies related to a person. Navgraha Pendant in OM is highly effective for warding off the malefic effects of all the nine planets (navgrah).
Sometimes more than one planets are adversely placed in ones horoscope or at times the correctness of the horoscope is doubtful due to non-availability of authentic data. Under such conditions, this pendent is very useful as all the semi-precious stones required to pacify the malefic effects of all the nine planets are studded in this single pendent itself.
The symbol OM is representative of Lord Ganesha who is also known as Vighnaharta which means Remover of all kinds of Obstacles. Hence, this symbol provides a very auspicious positive energy and wearer of this symbol remains free from any negative and evil energies.