Capsule pressure gauges are mechanical instruments designed to measure low pressures with high sensitivity. They use a pair of thin, corrugated capsules (capsule elements) that expand or contract under applied pressure. The movement of the capsules is mechanically transmitted to a pointer on a dial, providing a visual indication of pressure. These gauges are ideal for applications requiring precise measurement of low-pressure gases or liquids, where standard Bourdon tube gauges may lack accuracy.