The Series MP Mini-Photohelic? Differential Pressure Switch/Gage combines the time proven Minihelic? II differential pressure gage with two SPDT switching set points. The Mini-Photohelic? switch/gage is designed to measure and control positive, negative, or differential pressures consisting of non-combustible and non-corrosive gases. Gage reading is independent of switch operation. Switching status is visible by LED indicators located on the front and rear of the gage. Set points are adjusted with push buttons on the back of the unit