Standard Zinc-plated Steel with NBR diaphragm 225 psig wetted parts.
Switch adjustment ranges from vacuum through 4,600 psig depending on model. 400 Series Mechanical Heavy-Duty Pressure Switch, 1 SPDT Switch, 1/4 NPT Male, 300 psig to 2,900 psig (5,000 psig), Hirschmann 400 Series Mechanical Heavy-Duty Pressure Switch, 1 SPDT Switch, 7/16-20 SAE J514 FIG 34B, 145 psig to 1,160 psig 5,000 psig, Hirschmann.