Most divers have their SPG in a boot along with some other instruments. Depth gauge, compass, dive computers. Once in a while, the SPG should be popped out and its connection where the hose swivel is should be rinsed as well.
Accumulation of salt water or sediments can corrode the connection and accelerate the deterioration of the metal. This leads to most of the leaks and failure of submersible pressure gauges.
Other instruments might benefit from getting pulled out of the boot and rinsed as well.
SPG or Submersible Pressure Gauge is a gauge that translate the pressure from the tank to a unit that has measurable properties. Similar to the fuel gauge of a car. They can either be in PSI for imperial system or bar for metric system. They are the same as their regular non-submersible counterpart but sealed to block water from getting into the mechanism preventing corrosion.