This Tuning Fork is made in Aluminium metal and anodized with GOLD coating. The Cosmic OM Tuning Fork creates a vibration that resonates with the 'Cosmic Om.It opens up heart chakra, good for relaxation and meditation. It is based on 136.10 Hz All our Tuning Forks are made from special grade Aluminium alloy and frequency is guaranteed to tuned to an accuracy of +/- 0.25% which is very good for healing.