Model 1100 differential pH sensors from Process Control Automation (PCA) are designed for accurate and reliable pH measurements. The sensors offer automatic temperature compensation, ground loop error elimination, cable runs of up to 900 meters, and a convertible design for versatile mounting options. Features include a double junction reference and gel-filled electrodes for longer life and dependability. Applications include any critical pH monitoring and control situation. 978/747-4300; www.aquasensor.net.