The 128 Hz tuning fork (C3 on the piano) is used for a variety of issues. Paramedics and EMTs have used this fork to locate bone fractures. This particular fork increases nitric oxide levels the most. This is a gas produced naturally in the body. Nitric oxide has many functions in the body. It can act as a messenger between cells, a neurotransmitter, and a hormone. It helps dilate blood vessels, supports a healthy heart, boosts brain power, improves sexual health, and increases blood flow. The 128 tuning fork is particularly effective when placed on the rib heads, thoracic vertebrae, sternum, and hip bones. Two tuning forks gently tapped on the knees and held to the ears create a beautiful, long-lasting low tone that is great for grounding and relaxation. To listen, hold the 128 tuning fork by the stem and gently tap the weights on your knees or a tapping pad. Bring the tuning fork (or tuning forks) to your ears and adjust the distance with the tone. Hold one fork about 1 inch from your left ear and another 1 inch from your right ear. This will create a long-lasting tone. Material: Aluminum alloy Color: Silver Package contents: 1 x 128HZ Tuning Fork 1 x Silicone Hammer 1 x Repair Tool 1 x Storage Bag Only the above package content, others are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.