3000MRS-125PA is a series 3000MRS Photohelic® switch/gauge combines the functions of a precise, highly repeatable differential pressure switch with a large easy-to-read analog pressure gauge employing the durable, time-proven Magnehelic® gauge design. The switch setting is easy to adjust with large external knobs on the gauge face. gauge reading is unaffected by switch operation - will indicate accurately even if power is interrupted. For applications requiring high cycle rates, choose 3000MRS model with SPST (N.O.) solid-state relays. Typical applications include pneumatic conveying, air conditioning systems and clean rooms.