1.Brain Tuners are based on brain wave studies using electroencephalography (EEG) technology to map different states of consciousness known as For , Theta, Alpha, and . 2.The Brain Tuner Tuning Fork Set is made from high quality Aluminum Alloy which is heat treated giving them a very pure tone. 3.The product includes forks 256, 259, 262, 267 and 271 hz for , Theta, Alpha, and waves. 4.For is associated with deep sleep. 5.Theta is associated with meditation and dream states. 6.Alpha is associated with relaxed awareness, creativity, and heightened learning. 7.For is associated with high alertness and focus. Color: As shown Material: Metal + Wood Package Contents: 1 x Tuning Fork Set Only the above package content, other products 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.