Adjustable Pressure Switches from Buyers Products can be custom set to a specific PSI. They trigger a signal when oil pressure is too low or high. The unit can be wired normally open or normally closed. Two models are available: – PS2575 is adjustable between 25-75 PSI and fits in any 1/8 in. NPT port. – PS2501K is adjustable between 250-1,000 PSI and fits a 1/4 in. NPT port (ideal for high pressure lines).