Those tuning forks are made of aluminum alloy and designed to meet medical requirements, the frequency of the tuning fork helps test hearing capabilities as well as with testing for bone fractures. 

128, 256, 512, 1024， 2048Hz frequency version are all available.

Products produced by a professional tuning fork factory from China, with reliable quality and economic costs, please feel free to discuss with us. Email: limed@263.net.