3 Mukhi Bead is known to be one of the most powerful for stopping all problems created in the past and existing in the present moment and about to take place in the Future. This Bead combined with appropriate Mantras helps to dramatically change a persons life for the better in the 40 days it takes to complete an initial Mantra Discipline. The 3 Mukhi Bead is a life saver. The wearer feels its influence by attaining success in his efforts, favourable means, learning and knowledge. Its best virtue is that it makes the wearer free from chronic fever certainly. It contains the Trinity of Gods: Brahma, Vishnu and Mahesh.

Excerpts from Books of Knowledge

Siva Purana Vidyesvara Samhita Translated by Shastri 1973
Suta said - is a favorite bead of Siva. It is highly sanctifying. It removes all sins by sight, contact and japas
Translation: SIVA said - If a man is not liberated after Meditation and acquisition of Knowledge, he shall wear . He shall be freed from all sins and attain the highest goal. A of 3 Faces always bestows means of enjoyment. As a result of its power all lures become firmly established. O! daughter of king of mountains thus I have explained to you the different types of based on the number of faces.

Padma Purana Chapter 57 Translated by Bhatta 1989
THE LORD said - The one with three mouths is Fire Himself; the sin earned in the past births of him on whom it remains is burnt as fire burns fuel. A wise man obtains that fruit which is obtained by worshipping Fire or by rites of honoring Fire or by offering the oblation of ghee; and also obtains heaven. He who wears a of three mouths on his body is like Brahma on the earth. It would burn all the sins due to wicked deeds collected in birth after birth. There would be not disease in his belly; he would not be sick. He is never defeated, and his house is not burnt by fire. These and all other fruits are obtained and destructive weapons also are warded off. Nothing inauspicious happens due to wearing of of three mouths i.e. when a of three mouths is worn on one's person.

Rudraksajabalapanisad
KALAGNI RUDRA replied - The one with three faces is Fire Himself, which on wearing pleases all the three Fire deities. In the Introduction Section of the Book RUDRAKSA Planetary Correlations and Astrological Implications of are detailed as follows:-  It is effective in therapies related to the bones, right eye, sight, heart and stomach etc. caused by the malefic effects of Sun.

Gems and by Mr. Anil Gupta he describes the Values and Merits of the 3 Mukhi Bead as follows:- 
Three Faced has three natural lines. The Agni purifies every thing in the same way, the wearer of 3 Faced gets rid of the sins that he had done in his past life and returns to the purely true life. It is the best for those who have fallen prey to inferiority complex or fear stricken and suffer from self hatred or mental strain. In a short time after wearing it, the wearer feels its influence by attaining success in his efforts, favorable means, learning and knowledge. Its another best virtue is that it makes the wearer free from chronic fever certainly. Modern physicists and allopathic doctors accept that the patient of the fever that comes after every 3 days, is cured. It contains the Trinity of gods Brahma and Vishnu and Mahesh and the trinity of Gunaas Sattva, Rajas and Tamas and the three spheres: The Sky, The Earth and The Paatal with their divine powers. For its divine powers this bead is the most sacred and powerful and the best.