"These chromium-plated forks can be used for the experiments of sound. There is a cross-section area of 5.5x8.5 mm. There are 8 sizes which uses different frequencies
(C) 256.0 Hz (D) 288.0 Hz (E) 320.0 Hz (F) 341.3 Hz
(G) 384.0 Hz (A) 426.7 Hz (B) 480.0 Hz (C) 512.0 Hz"