Raven S 60100 Filter Media Manager for Backwash Bed Expansion Red Light Sensor, Digital Readout, 25 Ft Cable Ensure EPA Compliant Filtration Media Manager Option:Square Rail Clamp NSF certification indicates the knife Size:12" x 2" x 1 1 2" A36 NSF certification indicates the knife meets established public health and sanitation standards Abrasion Resistant: Stay protected from wear and tear with the abrasion resistant design of this extension cord With a built in red light indicator and an intuitive display Stop guessing and start measuring with the Raven S 60100 Filter Media Manager—the essential tool for ensuring effective backwashing and regulatory compliance