There are four central parts to every Shore durometer gauge. First is the pressure foot. The pressure foot is located at the bottom of the gauge, perpendicular to the indentor. Second, the indentor, is a piece that sticks out of the pressure foot. The movement of the indentor during a measurement is what determines the hardness of the material being tested. Third is the calibrated swing. The calibrated swing is attached to the indentor and provides the source of resistance to the movement of the indentor. The accuracy of the calibrated spring has advanced a great deal technologically over the past several years. Finally, every durometer tested has an indicator, which true to its name indicates the hardness of the material at the end of the measurement. Indicators come in both digital and analog display formats.