Nepali two Mukhi Rudraksha has a natural hole in it. It is of good quality. Indonesian Rudraksha is of medium quality. Rudraksha from Haridwar and Hrishikesh has an artificial hole in it. So it is of lower quality. There is also a category of Badraksha from South India.
Two Mukhi Rudraksha represents Ardhnareeshwar Shiva Ji. It shows that this cosmos has dual energy i.e. male energy and female energy. When someone realizes this energy within himself, he becomes complete.

This is a combination of Chinese yin and yang( positive and negative energy) yet I think Yin Yang is not the most positive representation.
Agni (fire) is a male element that is in the raj of females. Chandra (water) is a female element that is in the veerya (semen) of males.
Bhagwan Shiva is the originator of the universe.

BENEFITS OF TWO MUKHI RUDRAKSHA
According to Padma Puran two face rudraksha has the boon from Fire God (Agni Dev). So, a wearer or a worshipper of this divine rudraksha gets the benefits of Yagna, Homa, and Agnihotra.
The wearer of two Mukhi rudraksha rids of the sin of cow slaughter.
This is good for harmony in life.
It effectively controls the malefic effects of the Moon and diseases of the left eye, kidney, intestines, etc.
When the moon is not well placed in one’s horoscope ( i.e. Moon- Rahu or Moon- Saturn). When there is Kemudrum yoga in the horoscope. When the Moon is between two malefic planets. When the Seventh house of a horoscope is afflicted. In all these conditions two Mukhi Rudraksha is highly effective.
It is very helpful in depression, anxiety, and concentration-related issues. It is used very effectively for mind programming.
This rudraksha is also called Deva-Deva because it prospers the wearer or worshiper both materially and spiritually.
Who should wear this divine 2 Mukhi Rudraksha
A person who is unmarried and has obstacles related to marriage.
A person who does not has harmony in his/her marital life.
This helps in progeny i.e. begetting a son.
Good for spiritual growth.
Mantra for chanting for two Mukhi Rudraksha
Om Namah (Shivpuran)
Om Om Namah (Mantramaharnava)
Om Khum (Padma Puran)
Om Shrim Namah
Purification/Energisation

There is a very rigorous and special process of Purification and Energisation. It is needed to unlock the maximum energy of a Rudraksha. It takes about a month to complete the process.
Purification & Energisation is a very important process without which no one should wear a Rudraksha. Rudraksha absorbs different types of energy before reaching you as it goes in many hands and many places.
So, nowadays this process becomes more important not only for unlocking the hidden potential of rudraksha but also for washing out unwanted energies.
Energy can not be unlocked without proper methods and constant practice. That’s why generally Rudrakshas do not operate in their full capacity. So, the next most important thing is Purification & Energisation of a Rudraksha
।।रुद्राक्षधारणच्श्रेष्ठम न किञ्चदापि विद्यते ।।
{ There is nothing best to wear Rudrakshas. Means Rudrakshas are the best solution for every kind of problem}
This sloka is mentioned in Shri Devi Bhagavatam (श्रीदेवीभागवतं महापुराणं).

To know more about Rudraksha
Watch Talk on Mystic Bead Rudraksha (Hindi)
Watch DANGERS of Manipulated 20 Face Rudraksha
Read about One Mukhi Rudraksha
Read about 14 Mukhi Rudraksha- Easy & High Growth