The calibration of the head is highly dependent on the age.

Head calibration and reduction can be implemented beautifully thanks to easier suppression of bone growth and development in the growth period of human, which is not sufficient but still possible until the mid 20s owing to the remaining flexibility of the bones.

However, the flexibility of the bones is low and the head bones are tightly packed in his mid-30s, so the change of head such as shrinkage and correction is minimal by the pressure of the HEADrang.

To sum up, the effect is not significant compared to the facial contour, but the pressure applied to the side cheeks can influence the temporal bone, middle of the forehead, splint bone, and lacrimal bone on the inside of the eye in a certain degree to induce the gradual change of head shape to a slim and western head contour. However, the effects vary depending on the age, but the effect may be exceptional for the asymmetric head.