Diaphragm pressure gauges are mechanical instruments used to measure low to medium pressures, especially in applications where the medium is corrosive, viscous, or contains solids. They operate using a flexible diaphragm that deflects under pressure; this deflection is mechanically transferred to a pointer on a dial, providing a visual reading. Diaphragm gauges are particularly useful in situations where standard Bourdon tube gauges might be damaged or provide inaccurate readings.