Fisher® C1 energy responsible controllers and transmitters continue the tradition of durable and dependable Fisher pressure instrumentation while addressing air/gas consumption concerns. The C1 Series is used wherever durable and dependable pressure instrumentation is required. The use of this product in demanding applications, such as those found in chemical process, gas, and oil production industries, demonstrates its versatility. The new design can reduce steady-state air/gas consumption to as little as 1/10th that of previous products. C1 Series controllers compare sensed process pressure (or differential pressure) with an operator-adjusted set point, and send a pneumatic signal to an adjacent control element that maintains the process pressure at or near the set point value. C1 Series transmitters sense process variables and send out a pneumatic signal, usually to an indicating or recording device that directly indicates the process measurement. Sour gas service capability: NACE-MRO175-2002.