As depicted here, in PSIS and PSIA measurement mode, the back side of the sensing element is sealed shut. Atmospheric pressure is not allowed into the chamber, so there is no compensation for changes in ambient pressure changes. When measuring very low pressures, this can result in large errors, but as pressure range increases, this error becomes smaller so as to eventually become insignificant. One big advantage of utilizing sealed transducers is that one path for moisture intrusion is eliminated. Also, by sealing the back side of the sensing element, higher pressure ranges are achieved. PSIG is limited to 300 psi, whereas sealed units can go to 7500 psi with the SSI transducer.