The Dwyer A3000 Series Photohelic® switches/gages function as versatile, highly repeatable pressure switches combined with a precise pressure gage employing the time-proven Magnehelic® gage design. The Photohelic® gage measures and controls positive, negative or differential pressures of air and compatible gases. Standard models are rated to 25 psig with options to 35 or 80 psig. Single pressure 36000S models measure to 6000 psig with a 9000 psig rating.