Amazon.com: Physics Tuning Forks, Set of 8, with Mallet - Scientific Pitch, C4 = 256Hz - Includes Wooden Storage Case - Designed for Scientifc and Physics Experiments - Eisco Labs : Musical Instruments
Amazon.com: Tuning Fork, 1024 Hz. C, Two octaves Above Middle C. for Medical Sensory, Science Experiments, Musical Instrument Tuning : Musical Instruments