The atmospheric pressure varies from place to place depending up on the altitude of the location and prevailing weather conditions. In such variable conditions, precise pressure measurement can be arrived only if a fixed (un-changing) reference point is established.

For this purpose we have developed element of Twin Bellows, one of the same is totally evacuated and sealed, which shall be the reference point for calibration i.e. Absolute Zero.

These twin bellows are connected through a special type of movement, by which any change in the atmospheric pressure is compensated, and thereby the gauge gives the absolute pressure irrespective of the location.