Harmonizing cylinders are also called "Cylinders of the Pharaoh".

From the time of the ancient Egyptians, harmonizers have been used for correcting any energetic imbalances, and for recharging and restoring vitality within the body. The shungite harmonizer is the yin harmonizer and should be held in the left hand, as it connects with the flow of lunar/female energy. The Yang - harmonizer should be kept in the right hand (it corresponds to the Yang or Sun half of the physical body)